Knowledge (XXG)

Lambda calculus definition

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6136: 5647: 4492: 9102: 8476: 8848: 8724: 6131:{\displaystyle {\begin{aligned}\operatorname {eval} &=\operatorname {eval} \ \operatorname {strategy} ]]\\\operatorname {apply} &=\operatorname {canonym} ,x]\\\operatorname {apply} &=x{\text{ if x does match the above.}}\\\operatorname {eval} &=\operatorname {eval} ]\\\operatorname {eval} &=L\\\operatorname {lazy} &=X\\\operatorname {eager} &=\operatorname {eval} \end{aligned}}} 4126: 9463: 9344: 6398: 8988: 8362: 2440: 8735: 8611: 43: 6624: 4487:{\displaystyle {\begin{aligned}\operatorname {canonym} &=\operatorname {canonym} \\\operatorname {canonym} &=\lambda \operatorname {name} (Q).\operatorname {canonym} ,Q+N]\\\operatorname {canonym} &=\operatorname {canonym} \ \operatorname {canonym} \\\operatorname {canonym} &=\operatorname {name} (M)\end{aligned}}} 9355: 9236: 6217: 3592:
The problem of how variables may be renamed is difficult. This definition avoids the problem by substituting all names with canonical names, which are constructed based on the position of the definition of the name in the expression. The approach is analogous to what a compiler does, but has been
6197: 9097:{\displaystyle (\lambda \operatorname {P} .\lambda \operatorname {PN} .(\lambda \operatorname {PNF} .(\lambda \operatorname {PNFNF} .\operatorname {PNF} \operatorname {PNFNF} )(\lambda \operatorname {PNFNS} .\operatorname {PNF} \operatorname {PNFNS} ))(\operatorname {P} \operatorname {PN} ))} 8471:{\displaystyle (\lambda \operatorname {P} .\lambda \operatorname {PN} .(\lambda \operatorname {PNF} .(\lambda \operatorname {PNFNF} .\operatorname {PNF} \operatorname {PNFNF} )(\lambda \operatorname {PNFNS} .\operatorname {PNF} \operatorname {PNFNS} ))(\operatorname {P} \operatorname {PN} ))} 2131: 8843:{\displaystyle (\lambda \operatorname {P} .\lambda \operatorname {PN} .((\lambda \operatorname {PNF} .({\color {Red}\operatorname {PNF} }\operatorname {PN} )\operatorname {PNF} )(\lambda \operatorname {PNS} .(\operatorname {P} {\color {Red}\operatorname {PNS} )}\operatorname {PNS} )))} 5017:
of a lambda expression, M, is denoted as FV(M). This is the set of variable names that have instances not bound (used) in a lambda abstraction, within the lambda expression. They are the variable names that may be bound to formal parameter variables from outside the lambda expression.
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A lambda expression that cannot be reduced further, by either β-redex, or η-redex is in normal form. Note that alpha-conversion may convert functions. All normal forms that can be converted into each other by α-conversion are defined to be equal. See the main article on
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The result may be different depending on the strategy used. Eager evaluation will apply all reductions possible, leaving the result in normal form, while lazy evaluation will omit some reductions in parameters, leaving the result in "weak head normal form".
9458:{\displaystyle (\lambda \operatorname {P} .\lambda \operatorname {PN} .((\lambda \operatorname {PNF} .(\operatorname {P} \operatorname {PN} )\operatorname {PNF} )(\lambda \operatorname {PNS} .(\operatorname {P} \operatorname {PN} )\operatorname {PNS} )))} 9339:{\displaystyle (\lambda \operatorname {P} .\lambda \operatorname {PN} .((\lambda \operatorname {PNF} .(\operatorname {P} \operatorname {PN} )\operatorname {PNF} )(\lambda \operatorname {PNS} .(\operatorname {P} \operatorname {PN} )\operatorname {PNS} )))} 7792: 7682: 5569:
The definitions given here assume that the first definition that matches the lambda expression will be used. This convention is used to make the definition more readable. Otherwise some if conditions would be required to make the definition precise.
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The precise rules for alpha-conversion are not completely trivial. First, when alpha-converting an abstraction, the only variable occurrences that are renamed are those that are bound by the same abstraction. For example, an alpha-conversion of
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This mathematical definition is structured so that it represents the result, and not the way it gets calculated. However the result may be different between lazy and eager evaluation. This difference is described in the evaluation formulas.
2123: 8150: 7978:β-reduction captures the idea of function application (also called a function call), and implements the substitution of the actual parameter expression for the formal parameter variable. β-reduction is defined in terms of substitution. 1285: 6393:{\displaystyle {\begin{aligned}\operatorname {normal} &=\operatorname {false} \\\operatorname {normal} &=\operatorname {false} \\\operatorname {normal} &=\operatorname {normal} \land \operatorname {normal} \end{aligned}}} 8982: 8356: 1210: 6452:(The definition below is flawed, it is in contradiction with the definition saying that weak head normal form is either head normal form or the term is an abstraction. The notion has been introduced by Simon Peyton Jones.) 6147: 3931: 9223: 8598: 9992: 9829: 2435:{\displaystyle {\begin{aligned}(M_{1}\ M_{2})&\equiv (M_{1})\ (M_{2})\\(\lambda x.M)&\equiv \lambda x.M\\(\lambda y.M)&\equiv \lambda y.(M){\text{, if }}x\neq y{\text{, provided }}y\notin FV(N)\end{aligned}}} 5282: 5531: 5447: 6685:
The canonical naming definition deals with the problem of variable identity by constructing a unique name for each variable based on the position of the lambda abstraction for the variable name in the expression.
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The formal parameter variable is said to bind the variable name wherever it occurs free in the body. Variable (names) that have already been matched to formal parameter variable are said to be
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The lambda abstraction operator, λ, takes a formal parameter variable and a body expression. When evaluated the formal parameter variable is identified with the value of the actual parameter.
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The naive β-redex changed the meaning of the expression because x and y from the actual parameter became captured when the expressions were substituted in the inner abstractions.
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Variables in a lambda expression may either be "bound" or "free". Bound variables are variable names that are already attached to formal parameter variables in the expression.
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Reductions to the function (the head) have been applied, but not all reductions to the parameter have been applied. This is the result obtained from applying lazy evaluation.
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The purpose of β-reduction is to calculate a value. A value in lambda calculus is a function. So β-reduction continues until the expression looks like a function abstraction.
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The alpha renaming removed the problem by changing the names of x and y in the inner abstraction so that they are distinct from the names of x and y in the actual parameter.
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of a lambda expression, M, is denoted as BV(M). This is the set of variable names that have instances bound (used) in a lambda abstraction, within the lambda expression.
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Execution is performing β-reductions and η-reductions on subexpressions in the canonym of a lambda expression until the result is a lambda function (abstraction) in the
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Canonym is a function that takes a lambda expression and renames all names canonically, based on their positions in the expression. This might be implemented as,
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Mathematicians will sometimes restrict a variable to be a single alphabetic character. When using this convention the comma is omitted from the variable list.
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is an η-redex. The expression to which a redex reduces is called its reduct; using the previous example, the reducts of these expressions are respectively
6192:{\displaystyle {\begin{aligned}\operatorname {strategy} &=\operatorname {lazy} \\\operatorname {strategy} &=\operatorname {eager} \end{aligned}}} 852:, is said to bind its variable wherever it occurs in the body of the abstraction. Variables that fall within the scope of an abstraction are said to be 3827: 9115: 8490: 9902: 9739: 1917: 1905: 1785:
Second, alpha-conversion is not possible if it would result in a variable getting captured by a different abstraction. For example, if we replace
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This is to stop bound variables with the same name being substituted. This would not have occurred in a canonically renamed lambda expression.
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This definition introduces the rules used in the standard definition and relates explains them in terms of the canonical renaming definition.
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In an α-conversion, names may be substituted for new names if the new name is not free in the body, as this would lead to the capture of
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The standard definition of lambda calculus uses some definitions which may be considered as theorems, which can be proved based on the
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Where, N is the string "N", F is the string "F", S is the string "S", + is concatenation, and "name" converts a string into a name
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To substitute into a lambda abstraction, it is sometimes necessary to α-convert the expression. For example, it is not correct for
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Alpha-conversion, sometimes known as alpha-renaming, allows bound variable names to be changed. For example, alpha-conversion of
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Alpha-conversion, sometimes known as alpha-renaming, allows bound variable names to be changed. For example, alpha-conversion of
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is a renaming of a lambda expression to give the expression standard names, based on the position of the name in the expression.
7939:{\displaystyle \lambda \operatorname {P} .\lambda \operatorname {PN} .({\color {Red}\operatorname {PN} }\operatorname {PN} )} 6980: 2593:β-reduction captures the idea of function application. β-reduction is defined in terms of substitution: the β-reduction of 3514: 10126: 9844: 9681: 7173: 7084: 96:. Two definitions of the language are given here: a standard definition, and a definition using mathematical formulas. 3384: 941:. Also note that a variable is bound by its "nearest" abstraction. In the following example the single occurrence of 745: 10367:, Studies in Logic and the Foundations of Mathematics, vol. 103 (Revised ed.), North Holland, Amsterdam., 9661:{\displaystyle {\begin{array}{r}((\lambda x.z\ x)(\lambda y.z\ y))\\((\lambda a.z\ a)(\lambda b.z\ b))\end{array}}} 6758: 3728: 6211:
All reductions that can be applied have been applied. This is the result obtained from applying eager evaluation.
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Note that rule 1 must be modified if it is to be used on non canonically renamed lambda expressions. See
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To keep the notation of lambda expressions uncluttered, the following conventions are usually applied.
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Note that the substitution will not recurse into the body of lambda expressions with formal parameter
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Lambda Calculus has a simple syntax. A lambda calculus program has the syntax of an expression where,
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The execution of a lambda expression proceeds using the following reductions and transformations,
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An abstraction with multiple parameters is equivalent to multiple abstractions of one parameter.
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Instances of rule 2 are known as abstractions and instances of rule 3 are known as applications.
8145:{\displaystyle (\forall z:z\not \in FV(y)\lor z\not \in BV(b))\to \operatorname {beta-redex} =b} 7989:
in the body, β-reduction may be performed on the lambda abstraction without canonical renaming.
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The meaning of lambda expressions is defined by how expressions can be transformed or reduced.
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was supposed to be free but ended up being bound. The correct substitution in this case is
1280:{\displaystyle \operatorname {FV} (M\ N)=\operatorname {FV} (M)\cup \operatorname {FV} (N)} 177: 150: 123: 10454: 10396: 484: 31: 4547: 4511: 2585:, up to α-equivalence. Notice that substitution is defined uniquely up to α-equivalence. 1294:. Closed lambda expressions are also known as combinators and are equivalent to terms in 10503: 10441: 8977:{\displaystyle (\lambda x.\lambda y.(\lambda z.(\lambda a.z\ a)(\lambda b.z\ b))(x\ y))} 8351:{\displaystyle (\lambda x.\lambda y.(\lambda z.(\lambda x.z\ x)(\lambda y.z\ y))(x\ y))} 10499: 10012: 10008: 8198: 8178: 8158: 7950: 7542: 4677: 4084: 4027: 4007: 3987: 3952: 2885: 2865: 2845: 2801: 2797: 2648: 2533: 2006: 1986: 1966: 1931: 1808: 1788: 1573: 1538: 1483: 1463: 1443: 1423: 1403: 1205:{\displaystyle \operatorname {FV} (\lambda x.M)=\operatorname {FV} (M)\backslash \{x\}} 1122: 1023: 944: 883: 863: 310: 262: 10105:
The problem with using an η-redex when f has free variables is shown in this example,
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In programming languages with static scope, alpha-conversion can be used to make
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The meaning of lambda expressions is defined by how expressions can be reduced.
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Lambda calculus is a formal mathematical system based on lambda abstraction and
9218:{\displaystyle (\lambda x.\lambda y.((\lambda a.(x\ y)a)(\lambda b.(x\ y)b)))} 8593:{\displaystyle (\lambda x.\lambda y.((\lambda x.(x\ y)x)(\lambda y.(x\ y)y)))} 6714:
For example, in the following expression y is a bound variable and x is free:
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Map from one value to another if the value is in the map. O is the empty map.
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they give the same result for all arguments. η-reduction converts between
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A Proof-Theoretic Account of Programming and the Role of Reduction Rules.
5526:{\displaystyle \mathrm {BV} (M\ N)=\mathrm {BV} (M)\cup \mathrm {BV} (N)} 5442:{\displaystyle \mathrm {FV} (M\ N)=\mathrm {FV} (M)\cup \mathrm {FV} (N)} 7314:, refers to subterms that can be reduced by one of the reduction rules. 4674:
If L is a lambda expression, x is a name, and y is a lambda expression;
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and is defined by recursion on the structure of the terms, as follows:
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is the set of variables that do not belong to a lambda abstraction in
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All α-conversions of a λ-expression are considered to be equivalent.
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A lambda abstraction has a lower precedence than an application, so;
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because of the change to the substitution operator described above.
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We also speak of the resulting equivalences: two expressions are
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In the form of a lambda abstraction whose body is not reducible.
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We also speak of the resulting equivalences: two expressions are
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This improper use of η-reduction changes the meaning by leaving
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Combine the bound variables from the function and the parameter
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Combine the free variables from the function and the parameter
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For example the previous rules would have wrongly translated,
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correctly rename y to k, (because k is not used in the body)
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The new rules block this substitution so that it remains as,
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An expression that contains no free variables is said to be
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A variable as used by computer scientists has the syntax,
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x (P) and y (PN) have been captured in the substitution.
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adapted to work within the constraints of mathematics.
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The implementation of functional programming languages
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Then the evaluation strategy may be chosen as either,
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The β-redex then proceeded with the intended meaning.
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The Bound Variable Set, BV, is used in the rule for
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may be too technical for most readers to understand
10336: 10294: 10260: 10211: 10178:{\displaystyle (\lambda x.(\lambda y.y\,x)\,x)\,a} 10177: 10094: 9986: 9889: 9823: 9726: 9660: 9457: 9338: 9217: 9096: 8976: 8842: 8718: 8592: 8470: 8350: 8207: 8187: 8167: 8144: 7959: 7938: 7886: 7834: 7786: 7735: 7676: 7625: 7551: 7528: 7372: 7343: 7245: 7156: 7064: 6968: 6897: 6803: 6747: 6662: 6618: 6436: 6392: 6191: 6130: 5622: 5525: 5441: 5355: 5276: 5195: 5151: 5098: 5059: 4990: 4930: 4870: 4784: 4701: 4658: 4586: 4535: 4486: 4093: 4073: 4036: 4016: 3996: 3976: 3925: 3814: 3715: 3562: 3497: 3435: 2894: 2874: 2854: 2834: 2780: 2712: 2677: 2637: 2577: 2542: 2522: 2487: 2434: 2117: 2015: 1995: 1975: 1955: 1893: 1855: 1817: 1797: 1774: 1732: 1694: 1648: 1619: 1582: 1562: 1527: 1492: 1472: 1452: 1432: 1412: 1392: 1279: 1204: 1131: 1111: 1064: 1032: 1006: 953: 933: 892: 872: 844: 816: 781: 732: 691: 650: 609: 565: 531: 499: 458: 420: 386: 345: 319: 297: 271: 243: 216: 193: 166: 139: 9890:{\displaystyle \operatorname {FV} (x\ y)=\{x,y\}} 9727:{\displaystyle \operatorname {FV} (x\ y)=\{x,y\}} 7986: 7982: 7388: 7246:{\displaystyle (\lambda x.x\ z)=(\lambda x.x\ z)} 7157:{\displaystyle (\lambda x.x\ z)=(\lambda x.y\ z)} 4047: 961:in the expression is bound by the second lambda: 541:Applications are assumed to be left-associative: 10478:Barendregt, Henk; Barendsen, Erik (March 2000), 7801:naively rename y to z, (wrong because z free in 6674:Derivation of standard from the math definition 5545:The Free Variable Set, FV is used above in the 3436:{\displaystyle \lambda x.y\ z=\lambda x.(y\ z)} 1400:is a β-redex in expressing the substitution of 782:{\displaystyle \lambda x.\lambda y.\lambda z.N} 5637:is a name prefix possibly an empty string and 3940: 1918:alpha renaming to make name resolution trivial 10364:The Lambda Calculus: Its Syntax and Semantics 10015:they give the same result for all arguments. 8862:Alpha rename inner, x → a, y → b 7291:: which captures a notion of extensionality ( 6804:{\displaystyle \lambda x.y\ (\lambda x.z\ x)} 4709:means substitute x by y in L. The rules are, 3815:{\displaystyle \operatorname {beta-redex} =b} 1336:: which captures a notion of extensionality ( 8: 10495: 10493: 9981: 9969: 9884: 9872: 9818: 9806: 9721: 9709: 5546: 5350: 5344: 5271: 5265: 5146: 5140: 5028:The rules for the two sets are given below. 1199: 1193: 1112:{\displaystyle \operatorname {FV} (x)=\{x\}} 1106: 1100: 10521: 10519: 7796:No change to canonical renamed expression. 5196:{\displaystyle \mathrm {BV} (x)=\emptyset } 1007:{\displaystyle \lambda x.y(\lambda x.z\ x)} 860:. For example, in the following expression 7887:{\displaystyle \lambda z.\lambda z.(z\ z)} 7736:{\displaystyle \lambda z.\lambda k.(z\ k)} 7626:{\displaystyle \lambda z.\lambda y.(z\ y)} 6819: 5573:Running or evaluating a lambda expression 3946: 1908:simpler by ensuring that no variable name 742:A sequence of abstractions is contracted: 10526:Turbak, Franklyn; Gifford, David (2008), 10431: 10330: 10316: 10288: 10274: 10254: 10247: 10230: 10205: 10191: 10171: 10164: 10157: 10128: 10054: 10034: 10026: 9904: 9846: 9741: 9683: 9484: 9482: 9357: 9238: 9117: 8990: 8870: 8818: 8778: 8737: 8694: 8654: 8613: 8492: 8364: 8244: 8200: 8180: 8160: 8062: 7997: 7952: 7923: 7900: 7849: 7806: 7749: 7698: 7639: 7588: 7544: 7485: 7399: 7356: 7327: 7281:: applying functions to their arguments ( 7264:There are three kinds of transformation: 7175: 7086: 6982: 6969:{\displaystyle (\lambda x.b)=\lambda x.b} 6916: 6898:{\displaystyle (\lambda p.b)=\lambda p.b} 6830: 6760: 6719: 6637: 6465: 6463: 6411: 6221: 6219: 6151: 6149: 5960: 5899: 5796: 5651: 5649: 5585: 5506: 5486: 5460: 5458: 5422: 5402: 5376: 5374: 5324: 5295: 5293: 5245: 5216: 5214: 5170: 5168: 5120: 5118: 5079: 5077: 5040: 5038: 4944: 4884: 4849: 4806: 4798: 4785:{\displaystyle (\lambda p.b)=\lambda p.b} 4717: 4679: 4600: 4549: 4513: 4130: 4128: 4086: 4054: 4029: 4009: 3989: 3954: 3855: 3829: 3732: 3730: 3612: 3610: 3516: 3454: 3386: 2887: 2867: 2847: 2809: 2725: 2693: 2650: 2598: 2555: 2535: 2500: 2450: 2402: 2388: 2231: 2197: 2159: 2146: 2135: 2133: 2097: 2033: 2031: 2008: 1988: 1968: 1933: 1868: 1830: 1810: 1790: 1749: 1707: 1669: 1632: 1603: 1575: 1540: 1505: 1485: 1465: 1445: 1425: 1405: 1364: 1326:: applying functions to their arguments ( 1218: 1146: 1124: 1080: 1045: 1025: 966: 946: 905: 885: 865: 837: 794: 747: 704: 663: 628: 578: 546: 512: 486: 433: 401: 387:{\displaystyle (\lambda x.M)\in \Lambda } 358: 332: 312: 284: 264: 236: 209: 185: 179: 158: 152: 131: 125: 80:Learn how and when to remove this message 64:, without removing the technical details. 10528:Design concepts in programming languages 10107: 8220: 7564: 5030: 2970: 2926: 10353: 5262: 2688:For example, assuming some encoding of 5623:{\displaystyle \operatorname {eval} ]} 5152:{\displaystyle \mathrm {FV} (x)=\{x\}} 4074:{\displaystyle \operatorname {FV} (f)} 1065:{\displaystyle \operatorname {FV} (M)} 8819: 8779: 8695: 8655: 7924: 2957:In the form of a lambda abstraction. 2720:, we have the following β-reduction: 1894:{\displaystyle \lambda y.\lambda y.y} 1856:{\displaystyle \lambda x.\lambda y.x} 1775:{\displaystyle \lambda y.\lambda x.y} 1733:{\displaystyle \lambda y.\lambda x.x} 1695:{\displaystyle \lambda x.\lambda x.x} 62:make it understandable to non-experts 7: 10420:Lecture Notes on the Lambda Calculus 10397:"Example for Rules of Associativity" 6814:Changes to the substitution operator 5003:Changes to the substitution operator 2941:No β- or η-reductions are possible. 1309:There are three kinds of reduction: 104:This formal definition was given by 10455:"Example for Rule of Associativity" 10361:Barendregt, Hendrik Pieter (1984), 10261:{\displaystyle (\lambda y.y\,x)\,a} 6680:definition as mathematical formulas 5556:of non canonical lambda expression. 3588:Definition as mathematical formulas 3446:Applications are left associative; 2638:{\displaystyle ((\lambda V.E)\ E')} 619:The body of an abstraction extends 481:Outermost parentheses are dropped: 116:Lambda expressions are composed of 10038: 10035: 10007:η-reduction expresses the idea of 9431: 9398: 9365: 9312: 9279: 9246: 9079: 8998: 8812: 8745: 8688: 8656: 8621: 8453: 8372: 8090: 8087: 8084: 8081: 8078: 8072: 8069: 8066: 8063: 8002: 7905: 7772: 7754: 7662: 7644: 7510: 7507: 7504: 7498: 7495: 7492: 7489: 7486: 5985: 5982: 5979: 5976: 5973: 5967: 5964: 5961: 5824: 5821: 5818: 5815: 5812: 5806: 5803: 5800: 5797: 5510: 5507: 5490: 5487: 5464: 5461: 5426: 5423: 5406: 5403: 5380: 5377: 5328: 5325: 5299: 5296: 5249: 5246: 5220: 5217: 5190: 5174: 5171: 5124: 5121: 5083: 5080: 5044: 5041: 3880: 3877: 3874: 3871: 3868: 3862: 3859: 3856: 3760: 3757: 3754: 3751: 3748: 3742: 3739: 3736: 3733: 3640: 3637: 3634: 3631: 3625: 3622: 3619: 3616: 3613: 2796:η-reduction expresses the idea of 459:{\displaystyle (M\ N)\in \Lambda } 453: 415: 381: 340: 292: 238: 25: 8175:to rename names that are free in 6748:{\displaystyle \lambda y.x\ x\ y} 3498:{\displaystyle x\ y\ z=(x\ y)\ z} 3216:The variable list is defined as, 934:{\displaystyle \lambda y.x\ x\ y} 856:. All other variables are called 7835:{\displaystyle \lambda y.(z\ y)} 5901: if x does match the above. 5286:Free variables of M excluding x 5099:{\displaystyle \mathrm {BV} (M)} 5060:{\displaystyle \mathrm {FV} (M)} 4991:{\displaystyle z\neq x\to (z)=z} 3984:is the substitution of the name 1901:, which is not at all the same. 1393:{\displaystyle (\lambda x.M)\ N} 733:{\displaystyle (\lambda x.M)\ N} 692:{\displaystyle \lambda x.(M\ N)} 204:the abstraction symbols lambda ' 41: 30:For a general introduction, see 10574:Peyton Jones, Simon L. (1987). 10481:Introduction to Lambda Calculus 3026:Anonymous function definition. 421:{\displaystyle M,N\in \Lambda } 231:The set of lambda expressions, 10337:{\displaystyle \lambda y.y\,x} 10295:{\displaystyle \lambda a.a\,x} 10251: 10232: 10212:{\displaystyle \lambda a.a\,a} 10168: 10161: 10142: 10130: 10083: 10080: 10071: 10059: 10051: 10048: 10042: 9963: 9960: 9939: 9936: 9915: 9912: 9866: 9854: 9800: 9797: 9776: 9773: 9752: 9749: 9703: 9691: 9651: 9648: 9636: 9627: 9624: 9621: 9600: 9597: 9576: 9573: 9566: 9563: 9551: 9542: 9539: 9536: 9515: 9512: 9491: 9488: 9452: 9449: 9446: 9440: 9428: 9416: 9413: 9407: 9395: 9383: 9380: 9359: 9333: 9330: 9327: 9321: 9309: 9297: 9294: 9288: 9276: 9264: 9261: 9240: 9212: 9209: 9206: 9200: 9188: 9176: 9173: 9167: 9155: 9143: 9140: 9119: 9091: 9088: 9076: 9073: 9070: 9049: 9046: 9025: 9013: 8992: 8971: 8968: 8956: 8953: 8950: 8929: 8926: 8905: 8893: 8872: 8837: 8834: 8831: 8823: 8809: 8797: 8794: 8788: 8775: 8763: 8760: 8739: 8713: 8710: 8707: 8701: 8685: 8673: 8670: 8664: 8651: 8639: 8636: 8615: 8587: 8584: 8581: 8575: 8563: 8551: 8548: 8542: 8530: 8518: 8515: 8494: 8465: 8462: 8450: 8447: 8444: 8423: 8420: 8399: 8387: 8366: 8345: 8342: 8330: 8327: 8324: 8303: 8300: 8279: 8267: 8246: 8155:Alpha renaming may be used on 8139: 8127: 8118: 8097: 8059: 8056: 8053: 8047: 8029: 8023: 7999: 7974:β-reduction (capture avoiding) 7933: 7920: 7881: 7869: 7829: 7817: 7781: 7769: 7730: 7718: 7671: 7659: 7620: 7608: 7523: 7517: 7482: 7479: 7476: 7464: 7446: 7431: 7422: 7416: 7401: 7240: 7219: 7213: 7201: 7198: 7177: 7151: 7130: 7124: 7112: 7109: 7088: 7059: 7047: 7029: 7017: 7014: 6999: 6996: 6948: 6936: 6933: 6918: 6892: 6880: 6862: 6850: 6847: 6832: 6798: 6777: 6651: 6645: 6609: 6603: 6587: 6575: 6552: 6549: 6537: 6525: 6502: 6493: 6478: 6475: 6425: 6419: 6383: 6377: 6365: 6359: 6343: 6331: 6308: 6305: 6293: 6281: 6258: 6249: 6234: 6231: 6121: 6115: 6099: 6093: 6070: 6064: 6041: 6035: 6022: 6019: 6016: 6004: 5992: 5957: 5941: 5938: 5926: 5914: 5886: 5880: 5867: 5858: 5849: 5834: 5831: 5793: 5777: 5768: 5753: 5750: 5737: 5734: 5731: 5725: 5713: 5707: 5698: 5689: 5673: 5661: 5617: 5614: 5602: 5593: 5520: 5514: 5500: 5494: 5480: 5468: 5436: 5430: 5416: 5410: 5396: 5384: 5338: 5332: 5318: 5303: 5259: 5253: 5239: 5224: 5184: 5178: 5134: 5128: 5093: 5087: 5054: 5048: 4979: 4967: 4964: 4958: 4955: 4919: 4907: 4904: 4898: 4895: 4865: 4853: 4846: 4834: 4825: 4813: 4810: 4800: 4779: 4767: 4749: 4737: 4734: 4719: 4696: 4684: 4659:{\displaystyle x\neq z\to M=M} 4653: 4647: 4638: 4632: 4629: 4617: 4611: 4575: 4569: 4566: 4554: 4524: 4518: 4477: 4474: 4468: 4462: 4446: 4428: 4415: 4391: 4379: 4355: 4339: 4315: 4302: 4287: 4275: 4263: 4251: 4245: 4226: 4199: 4186: 4168: 4152: 4140: 4068: 4062: 3971: 3959: 3914: 3911: 3899: 3887: 3852: 3849: 3843: 3809: 3797: 3788: 3767: 3710: 3701: 3695: 3689: 3677: 3665: 3656: 3653: 3647: 3486: 3474: 3430: 3418: 2835:{\displaystyle \lambda x.(fx)} 2829: 2820: 2766: 2763: 2754: 2730: 2727: 2672: 2655: 2632: 2618: 2603: 2600: 2572: 2557: 2517: 2502: 2482: 2470: 2467: 2452: 2425: 2419: 2385: 2382: 2370: 2364: 2345: 2333: 2330: 2315: 2289: 2277: 2274: 2259: 2252: 2249: 2237: 2224: 2218: 2215: 2203: 2190: 2180: 2168: 2165: 2139: 2084: 2072: 2052: 2040: 1950: 1938: 1557: 1545: 1528:{\displaystyle \lambda x.M\ x} 1381: 1366: 1274: 1268: 1256: 1250: 1238: 1226: 1187: 1181: 1169: 1154: 1094: 1088: 1059: 1053: 1001: 980: 721: 706: 686: 674: 651:{\displaystyle \lambda x.M\ N} 604: 595: 583: 580: 526: 514: 447: 435: 375: 360: 1: 5547:definition of the η-reduction 5365:Bound variables of M plus x. 2578:{\displaystyle (\lambda z.x)} 2523:{\displaystyle (\lambda x.x)} 2488:{\displaystyle (\lambda x.y)} 817:{\displaystyle \lambda xyz.N} 346:{\displaystyle M\in \Lambda } 298:{\displaystyle x\in \Lambda } 7985:in the actual parameter and 7271:: changing bound variables ( 5009:Free and bound variable sets 4931:{\displaystyle z=x\to (z)=y} 1316:: changing bound variables ( 7373:{\displaystyle \lambda y.y} 7344:{\displaystyle \lambda x.x} 4871:{\displaystyle (X\,Y)=X\,Y} 2713:{\displaystyle 2,7,\times } 1649:{\displaystyle \lambda y.y} 1620:{\displaystyle \lambda x.x} 610:{\displaystyle ((M\ N)\ P)} 10622: 10530:, MIT press, p. 251, 3173:E.g. x, y, fact, sum, ... 2909: 2530:, because the substituted 832:The abstraction operator, 573:may be written instead of 29: 10513:(4), pages 265-282, 1988. 9899:The bound variables are, 9736:The bound variables are, 7981:If no variable names are 6818:In the definition of the 4116:Canonym - Canonical Names 4004:by the lambda expression 10417:Selinger, Peter (2008), 9841:The free variables are, 9678:The free variables are, 6693:Free and bound variables 3266: 3218: 3181: 3146: 3112: 3068: 3034: 2988: 2964:Syntax definition in BNF 2882:does not appear free in 1020:of a lambda expression, 880:is a bound variable and 845:{\displaystyle \lambda } 828:Free and bound variables 621:as far right as possible 244:{\displaystyle \Lambda } 217:{\displaystyle \lambda } 6908:must be replaced with, 1912:a name in a containing 566:{\displaystyle M\ N\ P} 10500:de Queiroz, Ruy J.G.B. 10338: 10296: 10262: 10213: 10179: 10096: 9988: 9891: 9825: 9728: 9662: 9471:x and y not captured. 9459: 9340: 9219: 9098: 8978: 8844: 8720: 8594: 8480:Original expressions. 8472: 8352: 8209: 8189: 8169: 8146: 7961: 7940: 7888: 7836: 7788: 7737: 7686:Original expressions. 7678: 7627: 7553: 7530: 7374: 7345: 7247: 7158: 7066: 6970: 6899: 6805: 6749: 6664: 6620: 6438: 6394: 6193: 6132: 5624: 5527: 5443: 5357: 5278: 5205:where x is a variable 5197: 5161:where x is a variable 5153: 5100: 5061: 4992: 4932: 4872: 4786: 4703: 4660: 4588: 4537: 4488: 4095: 4075: 4038: 4018: 3998: 3978: 3927: 3816: 3717: 3564: 3499: 3437: 3210:Bracketed expression. 2896: 2876: 2856: 2836: 2782: 2714: 2679: 2639: 2579: 2544: 2524: 2489: 2436: 2119: 2017: 1997: 1977: 1957: 1928:Substitution, written 1895: 1857: 1819: 1799: 1776: 1734: 1696: 1650: 1621: 1584: 1564: 1529: 1494: 1474: 1454: 1434: 1414: 1394: 1281: 1206: 1133: 1113: 1066: 1034: 1008: 955: 935: 894: 874: 846: 818: 783: 734: 693: 652: 611: 567: 533: 532:{\displaystyle (M\ N)} 501: 460: 422: 388: 347: 321: 299: 273: 245: 218: 195: 168: 141: 27:Mathematical formalism 10339: 10297: 10263: 10214: 10180: 10097: 9989: 9892: 9826: 9729: 9663: 9460: 9341: 9220: 9099: 8979: 8845: 8721: 8595: 8473: 8353: 8210: 8190: 8170: 8147: 7962: 7941: 7889: 7837: 7789: 7738: 7679: 7628: 7554: 7531: 7375: 7346: 7285:), calling functions; 7248: 7159: 7067: 6971: 6900: 6820:Substitution Operator 6806: 6750: 6665: 6621: 6448:Weak head normal form 6439: 6395: 6194: 6133: 5625: 5528: 5444: 5358: 5279: 5198: 5154: 5106:- Bound Variable Set 5101: 5062: 4993: 4933: 4873: 4787: 4704: 4670:Substitution operator 4661: 4589: 4538: 4489: 4096: 4076: 4039: 4024:in lambda expression 4019: 3999: 3979: 3947:Substitution Operator 3928: 3817: 3718: 3565: 3500: 3438: 2954:Weak Head Normal Form 2897: 2877: 2857: 2837: 2783: 2715: 2680: 2640: 2580: 2545: 2525: 2490: 2437: 2120: 2018: 1998: 1978: 1958: 1896: 1858: 1820: 1800: 1777: 1735: 1697: 1651: 1622: 1585: 1565: 1530: 1495: 1475: 1455: 1435: 1415: 1395: 1282: 1207: 1134: 1114: 1067: 1035: 1009: 956: 936: 895: 875: 847: 819: 784: 735: 694: 653: 612: 568: 534: 502: 461: 423: 389: 348: 322: 300: 274: 246: 219: 196: 194:{\displaystyle v_{n}} 169: 167:{\displaystyle v_{2}} 142: 140:{\displaystyle v_{1}} 18:Weak head normal form 10315: 10273: 10229: 10190: 10127: 10025: 9903: 9845: 9740: 9682: 9481: 9356: 9237: 9116: 8989: 8869: 8736: 8612: 8491: 8363: 8243: 8199: 8179: 8159: 7996: 7951: 7899: 7848: 7805: 7748: 7697: 7638: 7587: 7543: 7398: 7355: 7326: 7312:reducible expression 7174: 7085: 6981: 6915: 6829: 6759: 6718: 6636: 6629:In all other cases, 6462: 6410: 6403:In all other cases, 6218: 6148: 5648: 5584: 5457: 5373: 5292: 5213: 5167: 5117: 5076: 5067:- Free Variable Set 5037: 4943: 4883: 4797: 4716: 4678: 4599: 4548: 4512: 4127: 4085: 4053: 4028: 4008: 3988: 3953: 3828: 3729: 3609: 3580:y is a variable list 3515: 3453: 3385: 2886: 2866: 2846: 2808: 2724: 2692: 2649: 2597: 2554: 2534: 2499: 2449: 2132: 2030: 2007: 1987: 1967: 1932: 1867: 1829: 1809: 1789: 1748: 1706: 1668: 1631: 1602: 1574: 1539: 1504: 1484: 1464: 1444: 1424: 1404: 1363: 1357:reducible expression 1217: 1145: 1123: 1079: 1044: 1024: 965: 945: 904: 884: 864: 836: 793: 746: 703: 662: 627: 577: 545: 511: 500:{\displaystyle M\ N} 485: 432: 400: 357: 331: 311: 283: 279:is a variable, then 263: 235: 208: 178: 151: 124: 94:function application 10442:2008arXiv0804.3434S 5561:Evaluation strategy 4587:{\displaystyle M=y} 4536:{\displaystyle O=x} 253:defined inductively 100:Standard definition 10457:. Lambda-bound.com 10399:. Lambda-bound.com 10334: 10292: 10258: 10223:Naive η-reduction 10209: 10175: 10092: 9984: 9887: 9821: 9724: 9671:In this example, 9658: 9656: 9455: 9336: 9215: 9094: 8974: 8840: 8826: 8783: 8716: 8699: 8659: 8590: 8468: 8348: 8230:Canonically named 8205: 8185: 8165: 8142: 7957: 7936: 7928: 7884: 7832: 7784: 7733: 7674: 7623: 7574:Canonically named 7549: 7526: 7370: 7341: 7243: 7154: 7062: 6966: 6895: 6801: 6745: 6660: 6616: 6614: 6434: 6390: 6388: 6189: 6187: 6128: 6126: 5620: 5523: 5439: 5353: 5274: 5193: 5149: 5096: 5057: 4988: 4928: 4868: 4782: 4699: 4656: 4584: 4533: 4484: 4482: 4091: 4071: 4034: 4014: 3994: 3974: 3923: 3812: 3713: 3583:z is an expression 3560: 3495: 3433: 2892: 2872: 2852: 2832: 2778: 2710: 2675: 2635: 2575: 2540: 2520: 2485: 2432: 2430: 2115: 2113: 2013: 1993: 1983:in the expression 1973: 1953: 1891: 1853: 1815: 1795: 1772: 1730: 1692: 1646: 1617: 1580: 1560: 1525: 1490: 1470: 1450: 1430: 1410: 1390: 1277: 1202: 1129: 1109: 1062: 1030: 1004: 951: 931: 890: 870: 842: 814: 789:is abbreviated as 779: 730: 689: 648: 607: 563: 529: 497: 456: 418: 384: 343: 327:is a variable and 317: 295: 269: 241: 214: 191: 164: 137: 10585:978-0-13-453333-9 10555:scholar.google.ca 10537:978-0-262-20175-9 10374:978-0-444-87508-2 10305: 10304: 10114:Lambda expression 10057: 9956: 9932: 9862: 9793: 9769: 9699: 9644: 9617: 9593: 9559: 9532: 9508: 9475: 9474: 9468: 9467: 9196: 9163: 8964: 8946: 8922: 8853: 8852: 8571: 8538: 8338: 8320: 8296: 8208:{\displaystyle b} 8188:{\displaystyle y} 8168:{\displaystyle b} 8114: 8077: 7971: 7970: 7960:{\displaystyle z} 7877: 7825: 7726: 7616: 7552:{\displaystyle x} 7503: 7236: 7194: 7147: 7105: 6995: 6794: 6776: 6741: 6735: 6583: 6545: 6498: 6339: 6301: 6254: 6012: 5972: 5934: 5902: 5854: 5811: 5773: 5718: 5669: 5539: 5538: 5476: 5392: 4702:{\displaystyle L} 4384: 4323: 4094:{\displaystyle f} 4048:Free Variable Set 4037:{\displaystyle b} 4017:{\displaystyle v} 3997:{\displaystyle p} 3977:{\displaystyle b} 3907: 3867: 3784: 3747: 3630: 3491: 3482: 3467: 3461: 3426: 3402: 3214: 3213: 3104:A function call. 2961: 2960: 2895:{\displaystyle f} 2875:{\displaystyle x} 2855:{\displaystyle f} 2759: 2744: 2678:{\displaystyle E} 2623: 2543:{\displaystyle x} 2405: 2391: 2223: 2154: 2100: 2016:{\displaystyle R} 1996:{\displaystyle E} 1976:{\displaystyle V} 1956:{\displaystyle E} 1818:{\displaystyle y} 1798:{\displaystyle x} 1583:{\displaystyle M} 1563:{\displaystyle M} 1521: 1493:{\displaystyle M} 1473:{\displaystyle x} 1453:{\displaystyle M} 1433:{\displaystyle x} 1413:{\displaystyle N} 1386: 1296:combinatory logic 1234: 1132:{\displaystyle x} 1033:{\displaystyle M} 997: 954:{\displaystyle x} 927: 921: 893:{\displaystyle x} 873:{\displaystyle y} 726: 682: 644: 600: 591: 559: 553: 522: 493: 443: 320:{\displaystyle x} 272:{\displaystyle x} 90: 89: 82: 16:(Redirected from 10613: 10590: 10589: 10571: 10565: 10564: 10562: 10561: 10547: 10541: 10540: 10523: 10514: 10497: 10488: 10487: 10486: 10475: 10466: 10465: 10463: 10462: 10451: 10445: 10444: 10435: 10425: 10414: 10408: 10407: 10405: 10404: 10393: 10387: 10382: 10377:, archived from 10358: 10343: 10341: 10340: 10335: 10310: 10301: 10299: 10298: 10293: 10267: 10265: 10264: 10259: 10218: 10216: 10215: 10210: 10184: 10182: 10181: 10176: 10108: 10101: 10099: 10098: 10093: 10058: 10055: 10041: 9993: 9991: 9990: 9985: 9954: 9930: 9896: 9894: 9893: 9888: 9860: 9830: 9828: 9827: 9822: 9791: 9767: 9733: 9731: 9730: 9725: 9697: 9675:In the β-redex, 9667: 9665: 9664: 9659: 9657: 9642: 9615: 9591: 9557: 9530: 9506: 9464: 9462: 9461: 9456: 9345: 9343: 9342: 9337: 9228: 9227: 9224: 9222: 9221: 9216: 9194: 9161: 9103: 9101: 9100: 9095: 8983: 8981: 8980: 8975: 8962: 8944: 8920: 8849: 8847: 8846: 8841: 8827: 8784: 8725: 8723: 8722: 8717: 8700: 8660: 8603: 8602: 8599: 8597: 8596: 8591: 8569: 8536: 8477: 8475: 8474: 8469: 8357: 8355: 8354: 8349: 8336: 8318: 8294: 8221: 8214: 8212: 8211: 8206: 8194: 8192: 8191: 8186: 8174: 8172: 8171: 8166: 8151: 8149: 8148: 8143: 8112: 8093: 8075: 7966: 7964: 7963: 7958: 7945: 7943: 7942: 7937: 7929: 7893: 7891: 7890: 7885: 7875: 7841: 7839: 7838: 7833: 7823: 7793: 7791: 7790: 7785: 7742: 7740: 7739: 7734: 7724: 7683: 7681: 7680: 7675: 7632: 7630: 7629: 7624: 7614: 7565: 7558: 7556: 7555: 7550: 7535: 7533: 7532: 7527: 7513: 7501: 7379: 7377: 7376: 7371: 7350: 7348: 7347: 7342: 7252: 7250: 7249: 7244: 7234: 7192: 7163: 7161: 7160: 7155: 7145: 7103: 7071: 7069: 7068: 7063: 6993: 6975: 6973: 6972: 6967: 6904: 6902: 6901: 6896: 6810: 6808: 6807: 6802: 6792: 6774: 6754: 6752: 6751: 6746: 6739: 6733: 6669: 6667: 6666: 6661: 6625: 6623: 6622: 6617: 6615: 6581: 6543: 6496: 6443: 6441: 6440: 6435: 6399: 6397: 6396: 6391: 6389: 6337: 6299: 6252: 6198: 6196: 6195: 6190: 6188: 6137: 6135: 6134: 6129: 6127: 6010: 5988: 5970: 5932: 5903: 5900: 5852: 5827: 5809: 5771: 5716: 5667: 5629: 5627: 5626: 5621: 5532: 5530: 5529: 5524: 5513: 5493: 5474: 5467: 5448: 5446: 5445: 5440: 5429: 5409: 5390: 5383: 5362: 5360: 5359: 5354: 5331: 5302: 5283: 5281: 5280: 5275: 5252: 5223: 5202: 5200: 5199: 5194: 5177: 5158: 5156: 5155: 5150: 5127: 5105: 5103: 5102: 5097: 5086: 5066: 5064: 5063: 5058: 5047: 5031: 4997: 4995: 4994: 4989: 4937: 4935: 4934: 4929: 4877: 4875: 4874: 4869: 4791: 4789: 4788: 4783: 4708: 4706: 4705: 4700: 4665: 4663: 4662: 4657: 4593: 4591: 4590: 4585: 4542: 4540: 4539: 4534: 4493: 4491: 4490: 4485: 4483: 4382: 4321: 4100: 4098: 4097: 4092: 4080: 4078: 4077: 4072: 4043: 4041: 4040: 4035: 4023: 4021: 4020: 4015: 4003: 4001: 4000: 3995: 3983: 3981: 3980: 3975: 3932: 3930: 3929: 3924: 3905: 3883: 3865: 3821: 3819: 3818: 3813: 3782: 3763: 3745: 3722: 3720: 3719: 3714: 3643: 3628: 3569: 3567: 3566: 3561: 3504: 3502: 3501: 3496: 3489: 3480: 3465: 3459: 3442: 3440: 3439: 3434: 3424: 3400: 3370: 3367: 3364: 3360: 3357: 3354: 3351: 3348: 3345: 3342: 3339: 3336: 3333: 3330: 3327: 3324: 3321: 3318: 3315: 3312: 3309: 3306: 3303: 3300: 3297: 3294: 3291: 3288: 3285: 3282: 3279: 3276: 3273: 3270: 3260: 3257: 3254: 3250: 3247: 3244: 3240: 3237: 3234: 3231: 3228: 3225: 3222: 3204: 3201: 3198: 3194: 3191: 3188: 3185: 3168: 3165: 3162: 3159: 3156: 3153: 3150: 3134: 3131: 3128: 3125: 3122: 3119: 3118:application-term 3116: 3099: 3096: 3093: 3090: 3087: 3086:application-term 3084: 3081: 3078: 3075: 3074:application-term 3072: 3056: 3053: 3052:application-term 3050: 3047: 3044: 3041: 3038: 3031:Application term 3021: 3018: 3015: 3011: 3008: 3005: 3001: 2998: 2995: 2992: 2971: 2946:Head Normal Form 2930:Normal Form Type 2927: 2922:Beta normal form 2912:Beta normal form 2901: 2899: 2898: 2893: 2881: 2879: 2878: 2873: 2861: 2859: 2858: 2853: 2841: 2839: 2838: 2833: 2787: 2785: 2784: 2779: 2757: 2742: 2719: 2717: 2716: 2711: 2684: 2682: 2681: 2676: 2671: 2644: 2642: 2641: 2636: 2631: 2621: 2584: 2582: 2581: 2576: 2549: 2547: 2546: 2541: 2529: 2527: 2526: 2521: 2494: 2492: 2491: 2486: 2441: 2439: 2438: 2433: 2431: 2406: 2404:, provided  2403: 2392: 2389: 2236: 2235: 2221: 2202: 2201: 2164: 2163: 2152: 2151: 2150: 2124: 2122: 2121: 2116: 2114: 2101: 2098: 2022: 2020: 2019: 2014: 2003:with expression 2002: 2000: 1999: 1994: 1982: 1980: 1979: 1974: 1962: 1960: 1959: 1954: 1900: 1898: 1897: 1892: 1862: 1860: 1859: 1854: 1824: 1822: 1821: 1816: 1804: 1802: 1801: 1796: 1781: 1779: 1778: 1773: 1739: 1737: 1736: 1731: 1702:could result in 1701: 1699: 1698: 1693: 1655: 1653: 1652: 1647: 1626: 1624: 1623: 1618: 1589: 1587: 1586: 1581: 1569: 1567: 1566: 1561: 1534: 1532: 1531: 1526: 1519: 1499: 1497: 1496: 1491: 1479: 1477: 1476: 1471: 1459: 1457: 1456: 1451: 1439: 1437: 1436: 1431: 1419: 1417: 1416: 1411: 1399: 1397: 1396: 1391: 1384: 1286: 1284: 1283: 1278: 1232: 1211: 1209: 1208: 1203: 1138: 1136: 1135: 1130: 1118: 1116: 1115: 1110: 1071: 1069: 1068: 1063: 1040:, is denoted as 1039: 1037: 1036: 1031: 1013: 1011: 1010: 1005: 995: 960: 958: 957: 952: 940: 938: 937: 932: 925: 919: 899: 897: 896: 891: 879: 877: 876: 871: 851: 849: 848: 843: 823: 821: 820: 815: 788: 786: 785: 780: 739: 737: 736: 731: 724: 698: 696: 695: 690: 680: 657: 655: 654: 649: 642: 616: 614: 613: 608: 598: 589: 572: 570: 569: 564: 557: 551: 538: 536: 535: 530: 520: 506: 504: 503: 498: 491: 465: 463: 462: 457: 441: 427: 425: 424: 419: 393: 391: 390: 385: 352: 350: 349: 344: 326: 324: 323: 318: 304: 302: 301: 296: 278: 276: 275: 270: 250: 248: 247: 242: 223: 221: 220: 215: 200: 198: 197: 192: 190: 189: 173: 171: 170: 165: 163: 162: 146: 144: 143: 138: 136: 135: 85: 78: 74: 71: 65: 45: 44: 37: 21: 10621: 10620: 10616: 10615: 10614: 10612: 10611: 10610: 10606:Lambda calculus 10596: 10595: 10594: 10593: 10586: 10573: 10572: 10568: 10559: 10557: 10549: 10548: 10544: 10538: 10525: 10524: 10517: 10498: 10491: 10484: 10477: 10476: 10469: 10460: 10458: 10453: 10452: 10448: 10423: 10416: 10415: 10411: 10402: 10400: 10395: 10394: 10390: 10375: 10360: 10359: 10355: 10350: 10344:unsubstituted. 10313: 10312: 10308: 10271: 10270: 10227: 10226: 10188: 10187: 10125: 10124: 10023: 10022: 10005: 9901: 9900: 9843: 9842: 9738: 9737: 9680: 9679: 9655: 9654: 9570: 9569: 9479: 9478: 9354: 9353: 9235: 9234: 9114: 9113: 8987: 8986: 8867: 8866: 8734: 8733: 8610: 8609: 8489: 8488: 8361: 8360: 8241: 8240: 8197: 8196: 8177: 8176: 8157: 8156: 7994: 7993: 7976: 7949: 7948: 7897: 7896: 7846: 7845: 7803: 7802: 7746: 7745: 7695: 7694: 7636: 7635: 7585: 7584: 7541: 7540: 7396: 7395: 7353: 7352: 7324: 7323: 7320: 7259: 7172: 7171: 7083: 7082: 6979: 6978: 6913: 6912: 6827: 6826: 6816: 6757: 6756: 6716: 6715: 6695: 6676: 6634: 6633: 6613: 6612: 6590: 6566: 6565: 6555: 6516: 6515: 6505: 6460: 6459: 6450: 6408: 6407: 6387: 6386: 6346: 6322: 6321: 6311: 6272: 6271: 6261: 6216: 6215: 6209: 6186: 6185: 6175: 6169: 6168: 6158: 6146: 6145: 6125: 6124: 6102: 6084: 6083: 6073: 6055: 6054: 6044: 6026: 6025: 5944: 5905: 5904: 5889: 5871: 5870: 5780: 5741: 5740: 5676: 5646: 5645: 5641:is defined by, 5582: 5581: 5563: 5455: 5454: 5371: 5370: 5290: 5289: 5211: 5210: 5165: 5164: 5115: 5114: 5074: 5073: 5035: 5034: 5023:bound variables 5011: 4941: 4940: 4881: 4880: 4795: 4794: 4714: 4713: 4676: 4675: 4672: 4597: 4596: 4546: 4545: 4510: 4509: 4503: 4481: 4480: 4449: 4419: 4418: 4342: 4306: 4305: 4229: 4190: 4189: 4155: 4125: 4124: 4118: 4083: 4082: 4051: 4050: 4026: 4025: 4006: 4005: 3986: 3985: 3951: 3950: 3826: 3825: 3727: 3726: 3607: 3606: 3605:α-conversion - 3599: 3590: 3577:x is a variable 3513: 3512: 3451: 3450: 3383: 3382: 3373: 3372: 3368: 3365: 3362: 3358: 3355: 3352: 3349: 3346: 3343: 3340: 3337: 3334: 3331: 3328: 3325: 3322: 3319: 3316: 3313: 3310: 3307: 3304: 3301: 3298: 3295: 3292: 3289: 3286: 3283: 3280: 3277: 3274: 3271: 3268: 3262: 3261: 3258: 3255: 3252: 3248: 3245: 3242: 3238: 3235: 3232: 3229: 3226: 3223: 3220: 3207: 3206: 3202: 3199: 3196: 3192: 3189: 3186: 3183: 3170: 3169: 3166: 3163: 3160: 3157: 3154: 3151: 3148: 3136: 3135: 3132: 3129: 3126: 3123: 3120: 3117: 3114: 3101: 3100: 3097: 3094: 3091: 3088: 3085: 3082: 3079: 3076: 3073: 3070: 3058: 3057: 3054: 3051: 3048: 3045: 3042: 3039: 3036: 3023: 3022: 3019: 3016: 3013: 3009: 3006: 3003: 2999: 2996: 2993: 2990: 2966: 2914: 2908: 2884: 2883: 2864: 2863: 2844: 2843: 2806: 2805: 2794: 2722: 2721: 2690: 2689: 2664: 2647: 2646: 2624: 2595: 2594: 2591: 2552: 2551: 2532: 2531: 2497: 2496: 2447: 2446: 2429: 2428: 2348: 2312: 2311: 2292: 2256: 2255: 2227: 2193: 2183: 2155: 2142: 2130: 2129: 2112: 2111: 2087: 2066: 2065: 2055: 2028: 2027: 2005: 2004: 1985: 1984: 1965: 1964: 1930: 1929: 1926: 1906:name resolution 1865: 1864: 1827: 1826: 1807: 1806: 1787: 1786: 1746: 1745: 1740:, but it could 1704: 1703: 1666: 1665: 1629: 1628: 1600: 1599: 1596: 1572: 1571: 1537: 1536: 1502: 1501: 1482: 1481: 1480:is not free in 1462: 1461: 1442: 1441: 1422: 1421: 1402: 1401: 1361: 1360: 1304: 1215: 1214: 1143: 1142: 1121: 1120: 1077: 1076: 1042: 1041: 1022: 1021: 963: 962: 943: 942: 902: 901: 882: 881: 862: 861: 834: 833: 830: 791: 790: 744: 743: 701: 700: 660: 659: 625: 624: 575: 574: 543: 542: 509: 508: 483: 482: 475: 430: 429: 398: 397: 355: 354: 329: 328: 309: 308: 281: 280: 261: 260: 233: 232: 227:parentheses ( ) 206: 205: 181: 176: 175: 154: 149: 148: 127: 122: 121: 114: 102: 86: 75: 69: 66: 58:help improve it 55: 46: 42: 35: 32:Lambda calculus 28: 23: 22: 15: 12: 11: 5: 10619: 10617: 10609: 10608: 10598: 10597: 10592: 10591: 10584: 10566: 10542: 10536: 10515: 10489: 10467: 10446: 10409: 10388: 10373: 10352: 10351: 10349: 10346: 10333: 10329: 10326: 10323: 10320: 10303: 10302: 10291: 10287: 10284: 10281: 10278: 10268: 10257: 10253: 10250: 10246: 10243: 10240: 10237: 10234: 10224: 10220: 10219: 10208: 10204: 10201: 10198: 10195: 10185: 10174: 10170: 10167: 10163: 10160: 10156: 10153: 10150: 10147: 10144: 10141: 10138: 10135: 10132: 10122: 10119: 10118: 10115: 10112: 10103: 10102: 10091: 10088: 10085: 10082: 10079: 10076: 10073: 10070: 10067: 10064: 10061: 10053: 10050: 10047: 10044: 10040: 10037: 10033: 10030: 10013:if and only if 10009:extensionality 10004: 10001: 10000: 9999: 9996: 9995: 9994: 9983: 9980: 9977: 9974: 9971: 9968: 9965: 9962: 9959: 9953: 9950: 9947: 9944: 9941: 9938: 9935: 9929: 9926: 9923: 9920: 9917: 9914: 9911: 9908: 9897: 9886: 9883: 9880: 9877: 9874: 9871: 9868: 9865: 9859: 9856: 9853: 9850: 9836: 9833: 9832: 9831: 9820: 9817: 9814: 9811: 9808: 9805: 9802: 9799: 9796: 9790: 9787: 9784: 9781: 9778: 9775: 9772: 9766: 9763: 9760: 9757: 9754: 9751: 9748: 9745: 9734: 9723: 9720: 9717: 9714: 9711: 9708: 9705: 9702: 9696: 9693: 9690: 9687: 9669: 9668: 9653: 9650: 9647: 9641: 9638: 9635: 9632: 9629: 9626: 9623: 9620: 9614: 9611: 9608: 9605: 9602: 9599: 9596: 9590: 9587: 9584: 9581: 9578: 9575: 9572: 9571: 9568: 9565: 9562: 9556: 9553: 9550: 9547: 9544: 9541: 9538: 9535: 9529: 9526: 9523: 9520: 9517: 9514: 9511: 9505: 9502: 9499: 9496: 9493: 9490: 9487: 9486: 9473: 9472: 9469: 9466: 9465: 9454: 9451: 9448: 9445: 9442: 9439: 9436: 9433: 9430: 9427: 9424: 9421: 9418: 9415: 9412: 9409: 9406: 9403: 9400: 9397: 9394: 9391: 9388: 9385: 9382: 9379: 9376: 9373: 9370: 9367: 9364: 9361: 9351: 9347: 9346: 9335: 9332: 9329: 9326: 9323: 9320: 9317: 9314: 9311: 9308: 9305: 9302: 9299: 9296: 9293: 9290: 9287: 9284: 9281: 9278: 9275: 9272: 9269: 9266: 9263: 9260: 9257: 9254: 9251: 9248: 9245: 9242: 9232: 9225: 9214: 9211: 9208: 9205: 9202: 9199: 9193: 9190: 9187: 9184: 9181: 9178: 9175: 9172: 9169: 9166: 9160: 9157: 9154: 9151: 9148: 9145: 9142: 9139: 9136: 9133: 9130: 9127: 9124: 9121: 9111: 9107: 9106: 9104: 9093: 9090: 9087: 9084: 9081: 9078: 9075: 9072: 9069: 9066: 9063: 9060: 9057: 9054: 9051: 9048: 9045: 9042: 9039: 9036: 9033: 9030: 9027: 9024: 9021: 9018: 9015: 9012: 9009: 9006: 9003: 9000: 8997: 8994: 8984: 8973: 8970: 8967: 8961: 8958: 8955: 8952: 8949: 8943: 8940: 8937: 8934: 8931: 8928: 8925: 8919: 8916: 8913: 8910: 8907: 8904: 8901: 8898: 8895: 8892: 8889: 8886: 8883: 8880: 8877: 8874: 8864: 8858: 8857: 8854: 8851: 8850: 8839: 8836: 8833: 8830: 8825: 8822: 8817: 8814: 8811: 8808: 8805: 8802: 8799: 8796: 8793: 8790: 8787: 8782: 8777: 8774: 8771: 8768: 8765: 8762: 8759: 8756: 8753: 8750: 8747: 8744: 8741: 8731: 8727: 8726: 8715: 8712: 8709: 8706: 8703: 8698: 8693: 8690: 8687: 8684: 8681: 8678: 8675: 8672: 8669: 8666: 8663: 8658: 8653: 8650: 8647: 8644: 8641: 8638: 8635: 8632: 8629: 8626: 8623: 8620: 8617: 8607: 8600: 8589: 8586: 8583: 8580: 8577: 8574: 8568: 8565: 8562: 8559: 8556: 8553: 8550: 8547: 8544: 8541: 8535: 8532: 8529: 8526: 8523: 8520: 8517: 8514: 8511: 8508: 8505: 8502: 8499: 8496: 8486: 8485:Naive beta 1, 8482: 8481: 8478: 8467: 8464: 8461: 8458: 8455: 8452: 8449: 8446: 8443: 8440: 8437: 8434: 8431: 8428: 8425: 8422: 8419: 8416: 8413: 8410: 8407: 8404: 8401: 8398: 8395: 8392: 8389: 8386: 8383: 8380: 8377: 8374: 8371: 8368: 8358: 8347: 8344: 8341: 8335: 8332: 8329: 8326: 8323: 8317: 8314: 8311: 8308: 8305: 8302: 8299: 8293: 8290: 8287: 8284: 8281: 8278: 8275: 8272: 8269: 8266: 8263: 8260: 8257: 8254: 8251: 8248: 8238: 8235: 8234: 8231: 8228: 8225: 8204: 8184: 8164: 8153: 8152: 8141: 8138: 8135: 8132: 8129: 8126: 8123: 8120: 8117: 8111: 8108: 8105: 8102: 8099: 8096: 8092: 8089: 8086: 8083: 8080: 8074: 8071: 8068: 8065: 8061: 8058: 8055: 8052: 8049: 8046: 8043: 8040: 8037: 8034: 8031: 8028: 8025: 8022: 8019: 8016: 8013: 8010: 8007: 8004: 8001: 7975: 7972: 7969: 7968: 7956: 7946: 7935: 7932: 7927: 7922: 7919: 7916: 7913: 7910: 7907: 7904: 7894: 7883: 7880: 7874: 7871: 7868: 7865: 7862: 7859: 7856: 7853: 7843: 7831: 7828: 7822: 7819: 7816: 7813: 7810: 7798: 7797: 7794: 7783: 7780: 7777: 7774: 7771: 7768: 7765: 7762: 7759: 7756: 7753: 7743: 7732: 7729: 7723: 7720: 7717: 7714: 7711: 7708: 7705: 7702: 7692: 7688: 7687: 7684: 7673: 7670: 7667: 7664: 7661: 7658: 7655: 7652: 7649: 7646: 7643: 7633: 7622: 7619: 7613: 7610: 7607: 7604: 7601: 7598: 7595: 7592: 7582: 7579: 7578: 7575: 7572: 7569: 7548: 7537: 7536: 7525: 7522: 7519: 7516: 7512: 7509: 7506: 7500: 7497: 7494: 7491: 7488: 7484: 7481: 7478: 7475: 7472: 7469: 7466: 7463: 7460: 7457: 7454: 7451: 7448: 7445: 7442: 7439: 7436: 7433: 7430: 7427: 7424: 7421: 7418: 7415: 7412: 7409: 7406: 7403: 7389:free variables 7369: 7366: 7363: 7360: 7340: 7337: 7334: 7331: 7319: 7316: 7297: 7296: 7286: 7276: 7258: 7257:Transformation 7255: 7254: 7253: 7242: 7239: 7233: 7230: 7227: 7224: 7221: 7218: 7215: 7212: 7209: 7206: 7203: 7200: 7197: 7191: 7188: 7185: 7182: 7179: 7165: 7164: 7153: 7150: 7144: 7141: 7138: 7135: 7132: 7129: 7126: 7123: 7120: 7117: 7114: 7111: 7108: 7102: 7099: 7096: 7093: 7090: 7073: 7072: 7061: 7058: 7055: 7052: 7049: 7046: 7043: 7040: 7037: 7034: 7031: 7028: 7025: 7022: 7019: 7016: 7013: 7010: 7007: 7004: 7001: 6998: 6992: 6989: 6986: 6976: 6965: 6962: 6959: 6956: 6953: 6950: 6947: 6944: 6941: 6938: 6935: 6932: 6929: 6926: 6923: 6920: 6906: 6905: 6894: 6891: 6888: 6885: 6882: 6879: 6876: 6873: 6870: 6867: 6864: 6861: 6858: 6855: 6852: 6849: 6846: 6843: 6840: 6837: 6834: 6815: 6812: 6800: 6797: 6791: 6788: 6785: 6782: 6779: 6773: 6770: 6767: 6764: 6744: 6738: 6732: 6729: 6726: 6723: 6694: 6691: 6675: 6672: 6671: 6670: 6659: 6656: 6653: 6650: 6647: 6644: 6641: 6627: 6626: 6611: 6608: 6605: 6602: 6599: 6596: 6593: 6591: 6589: 6586: 6580: 6577: 6574: 6571: 6568: 6567: 6564: 6561: 6558: 6556: 6554: 6551: 6548: 6542: 6539: 6536: 6533: 6530: 6527: 6524: 6521: 6518: 6517: 6514: 6511: 6508: 6506: 6504: 6501: 6495: 6492: 6489: 6486: 6483: 6480: 6477: 6474: 6471: 6468: 6467: 6449: 6446: 6445: 6444: 6433: 6430: 6427: 6424: 6421: 6418: 6415: 6401: 6400: 6385: 6382: 6379: 6376: 6373: 6370: 6367: 6364: 6361: 6358: 6355: 6352: 6349: 6347: 6345: 6342: 6336: 6333: 6330: 6327: 6324: 6323: 6320: 6317: 6314: 6312: 6310: 6307: 6304: 6298: 6295: 6292: 6289: 6286: 6283: 6280: 6277: 6274: 6273: 6270: 6267: 6264: 6262: 6260: 6257: 6251: 6248: 6245: 6242: 6239: 6236: 6233: 6230: 6227: 6224: 6223: 6208: 6205: 6200: 6199: 6184: 6181: 6178: 6176: 6174: 6171: 6170: 6167: 6164: 6161: 6159: 6157: 6154: 6153: 6139: 6138: 6123: 6120: 6117: 6114: 6111: 6108: 6105: 6103: 6101: 6098: 6095: 6092: 6089: 6086: 6085: 6082: 6079: 6076: 6074: 6072: 6069: 6066: 6063: 6060: 6057: 6056: 6053: 6050: 6047: 6045: 6043: 6040: 6037: 6034: 6031: 6028: 6027: 6024: 6021: 6018: 6015: 6009: 6006: 6003: 6000: 5997: 5994: 5991: 5987: 5984: 5981: 5978: 5975: 5969: 5966: 5963: 5959: 5956: 5953: 5950: 5947: 5945: 5943: 5940: 5937: 5931: 5928: 5925: 5922: 5919: 5916: 5913: 5910: 5907: 5906: 5898: 5895: 5892: 5890: 5888: 5885: 5882: 5879: 5876: 5873: 5872: 5869: 5866: 5863: 5860: 5857: 5851: 5848: 5845: 5842: 5839: 5836: 5833: 5830: 5826: 5823: 5820: 5817: 5814: 5808: 5805: 5802: 5799: 5795: 5792: 5789: 5786: 5783: 5781: 5779: 5776: 5770: 5767: 5764: 5761: 5758: 5755: 5752: 5749: 5746: 5743: 5742: 5739: 5736: 5733: 5730: 5727: 5724: 5721: 5715: 5712: 5709: 5706: 5703: 5700: 5697: 5694: 5691: 5688: 5685: 5682: 5679: 5677: 5675: 5672: 5666: 5663: 5660: 5657: 5654: 5653: 5631: 5630: 5619: 5616: 5613: 5610: 5607: 5604: 5601: 5598: 5595: 5592: 5589: 5562: 5559: 5558: 5557: 5550: 5537: 5536: 5533: 5522: 5519: 5516: 5512: 5509: 5505: 5502: 5499: 5496: 5492: 5489: 5485: 5482: 5479: 5473: 5470: 5466: 5463: 5452: 5449: 5438: 5435: 5432: 5428: 5425: 5421: 5418: 5415: 5412: 5408: 5405: 5401: 5398: 5395: 5389: 5386: 5382: 5379: 5367: 5366: 5363: 5352: 5349: 5346: 5343: 5340: 5337: 5334: 5330: 5327: 5323: 5320: 5317: 5314: 5311: 5308: 5305: 5301: 5298: 5287: 5284: 5273: 5270: 5267: 5264: 5261: 5258: 5255: 5251: 5248: 5244: 5241: 5238: 5235: 5232: 5229: 5226: 5222: 5219: 5207: 5206: 5203: 5192: 5189: 5186: 5183: 5180: 5176: 5173: 5162: 5159: 5148: 5145: 5142: 5139: 5136: 5133: 5130: 5126: 5123: 5111: 5110: 5107: 5095: 5092: 5089: 5085: 5082: 5071: 5068: 5056: 5053: 5050: 5046: 5043: 5015:free variables 5010: 5007: 4999: 4998: 4987: 4984: 4981: 4978: 4975: 4972: 4969: 4966: 4963: 4960: 4957: 4954: 4951: 4948: 4938: 4927: 4924: 4921: 4918: 4915: 4912: 4909: 4906: 4903: 4900: 4897: 4894: 4891: 4888: 4878: 4867: 4864: 4861: 4858: 4855: 4852: 4848: 4845: 4842: 4839: 4836: 4833: 4830: 4827: 4824: 4821: 4818: 4815: 4812: 4809: 4805: 4802: 4792: 4781: 4778: 4775: 4772: 4769: 4766: 4763: 4760: 4757: 4754: 4751: 4748: 4745: 4742: 4739: 4736: 4733: 4730: 4727: 4724: 4721: 4698: 4695: 4692: 4689: 4686: 4683: 4671: 4668: 4667: 4666: 4655: 4652: 4649: 4646: 4643: 4640: 4637: 4634: 4631: 4628: 4625: 4622: 4619: 4616: 4613: 4610: 4607: 4604: 4594: 4583: 4580: 4577: 4574: 4571: 4568: 4565: 4562: 4559: 4556: 4553: 4543: 4532: 4529: 4526: 4523: 4520: 4517: 4502: 4499: 4495: 4494: 4479: 4476: 4473: 4470: 4467: 4464: 4461: 4458: 4455: 4452: 4450: 4448: 4445: 4442: 4439: 4436: 4433: 4430: 4427: 4424: 4421: 4420: 4417: 4414: 4411: 4408: 4405: 4402: 4399: 4396: 4393: 4390: 4387: 4381: 4378: 4375: 4372: 4369: 4366: 4363: 4360: 4357: 4354: 4351: 4348: 4345: 4343: 4341: 4338: 4335: 4332: 4329: 4326: 4320: 4317: 4314: 4311: 4308: 4307: 4304: 4301: 4298: 4295: 4292: 4289: 4286: 4283: 4280: 4277: 4274: 4271: 4268: 4265: 4262: 4259: 4256: 4253: 4250: 4247: 4244: 4241: 4238: 4235: 4232: 4230: 4228: 4225: 4222: 4219: 4216: 4213: 4210: 4207: 4204: 4201: 4198: 4195: 4192: 4191: 4188: 4185: 4182: 4179: 4176: 4173: 4170: 4167: 4164: 4161: 4158: 4156: 4154: 4151: 4148: 4145: 4142: 4139: 4136: 4133: 4132: 4117: 4114: 4103: 4102: 4090: 4070: 4067: 4064: 4061: 4058: 4045: 4033: 4013: 3993: 3973: 3970: 3967: 3964: 3961: 3958: 3944: 3934: 3933: 3922: 3919: 3916: 3913: 3910: 3904: 3901: 3898: 3895: 3892: 3889: 3886: 3882: 3879: 3876: 3873: 3870: 3864: 3861: 3858: 3854: 3851: 3848: 3845: 3842: 3839: 3836: 3833: 3824:η-reduction - 3822: 3811: 3808: 3805: 3802: 3799: 3796: 3793: 3790: 3787: 3781: 3778: 3775: 3772: 3769: 3766: 3762: 3759: 3756: 3753: 3750: 3744: 3741: 3738: 3735: 3725:β-reduction - 3723: 3712: 3709: 3706: 3703: 3700: 3697: 3694: 3691: 3688: 3685: 3682: 3679: 3676: 3673: 3670: 3667: 3664: 3661: 3658: 3655: 3652: 3649: 3646: 3642: 3639: 3636: 3633: 3627: 3624: 3621: 3618: 3615: 3598: 3595: 3589: 3586: 3585: 3584: 3581: 3578: 3571: 3570: 3559: 3556: 3553: 3550: 3547: 3544: 3541: 3538: 3535: 3532: 3529: 3526: 3523: 3520: 3506: 3505: 3494: 3488: 3485: 3479: 3476: 3473: 3470: 3464: 3458: 3444: 3443: 3432: 3429: 3423: 3420: 3417: 3414: 3411: 3408: 3405: 3399: 3396: 3393: 3390: 3344:extension-char 3326:extension-char 3267: 3219: 3212: 3211: 3208: 3182: 3179: 3175: 3174: 3171: 3147: 3144: 3140: 3139: 3137: 3113: 3110: 3106: 3105: 3102: 3069: 3066: 3062: 3061: 3059: 3035: 3032: 3028: 3027: 3024: 2989: 2986: 2982: 2981: 2978: 2975: 2965: 2962: 2959: 2958: 2955: 2951: 2950: 2947: 2943: 2942: 2939: 2935: 2934: 2931: 2910:Main article: 2907: 2904: 2891: 2871: 2851: 2831: 2828: 2825: 2822: 2819: 2816: 2813: 2802:if and only if 2798:extensionality 2793: 2790: 2777: 2774: 2771: 2768: 2765: 2762: 2756: 2753: 2750: 2747: 2741: 2738: 2735: 2732: 2729: 2709: 2706: 2703: 2700: 2697: 2674: 2670: 2667: 2663: 2660: 2657: 2654: 2634: 2630: 2627: 2620: 2617: 2614: 2611: 2608: 2605: 2602: 2590: 2587: 2574: 2571: 2568: 2565: 2562: 2559: 2539: 2519: 2516: 2513: 2510: 2507: 2504: 2484: 2481: 2478: 2475: 2472: 2469: 2466: 2463: 2460: 2457: 2454: 2443: 2442: 2427: 2424: 2421: 2418: 2415: 2412: 2409: 2401: 2398: 2395: 2387: 2384: 2381: 2378: 2375: 2372: 2369: 2366: 2363: 2360: 2357: 2354: 2351: 2349: 2347: 2344: 2341: 2338: 2335: 2332: 2329: 2326: 2323: 2320: 2317: 2314: 2313: 2310: 2307: 2304: 2301: 2298: 2295: 2293: 2291: 2288: 2285: 2282: 2279: 2276: 2273: 2270: 2267: 2264: 2261: 2258: 2257: 2254: 2251: 2248: 2245: 2242: 2239: 2234: 2230: 2226: 2220: 2217: 2214: 2211: 2208: 2205: 2200: 2196: 2192: 2189: 2186: 2184: 2182: 2179: 2176: 2173: 2170: 2167: 2162: 2158: 2149: 2145: 2141: 2138: 2137: 2126: 2125: 2110: 2107: 2104: 2096: 2093: 2090: 2088: 2086: 2083: 2080: 2077: 2074: 2071: 2068: 2067: 2064: 2061: 2058: 2056: 2054: 2051: 2048: 2045: 2042: 2039: 2036: 2035: 2012: 1992: 1972: 1952: 1949: 1946: 1943: 1940: 1937: 1925: 1922: 1890: 1887: 1884: 1881: 1878: 1875: 1872: 1852: 1849: 1846: 1843: 1840: 1837: 1834: 1814: 1794: 1771: 1768: 1765: 1762: 1759: 1756: 1753: 1729: 1726: 1723: 1720: 1717: 1714: 1711: 1691: 1688: 1685: 1682: 1679: 1676: 1673: 1645: 1642: 1639: 1636: 1616: 1613: 1610: 1607: 1595: 1592: 1579: 1559: 1556: 1553: 1550: 1547: 1544: 1524: 1518: 1515: 1512: 1509: 1489: 1469: 1449: 1429: 1409: 1389: 1383: 1380: 1377: 1374: 1371: 1368: 1342: 1341: 1331: 1321: 1303: 1300: 1288: 1287: 1276: 1273: 1270: 1267: 1264: 1261: 1258: 1255: 1252: 1249: 1246: 1243: 1240: 1237: 1231: 1228: 1225: 1222: 1212: 1201: 1198: 1195: 1192: 1189: 1186: 1183: 1180: 1177: 1174: 1171: 1168: 1165: 1162: 1159: 1156: 1153: 1150: 1140: 1128: 1108: 1105: 1102: 1099: 1096: 1093: 1090: 1087: 1084: 1061: 1058: 1055: 1052: 1049: 1029: 1018:free variables 1003: 1000: 994: 991: 988: 985: 982: 979: 976: 973: 970: 950: 930: 924: 918: 915: 912: 909: 889: 869: 841: 829: 826: 825: 824: 813: 810: 807: 804: 801: 798: 778: 775: 772: 769: 766: 763: 760: 757: 754: 751: 740: 729: 723: 720: 717: 714: 711: 708: 688: 685: 679: 676: 673: 670: 667: 647: 641: 638: 635: 632: 617: 606: 603: 597: 594: 588: 585: 582: 562: 556: 550: 539: 528: 525: 519: 516: 496: 490: 474: 471: 467: 466: 455: 452: 449: 446: 440: 437: 417: 414: 411: 408: 405: 394: 383: 380: 377: 374: 371: 368: 365: 362: 342: 339: 336: 316: 305: 294: 291: 288: 268: 240: 229: 228: 225: 213: 202: 188: 184: 161: 157: 134: 130: 113: 110: 101: 98: 88: 87: 49: 47: 40: 26: 24: 14: 13: 10: 9: 6: 4: 3: 2: 10618: 10607: 10604: 10603: 10601: 10587: 10581: 10577: 10570: 10567: 10556: 10552: 10546: 10543: 10539: 10533: 10529: 10522: 10520: 10516: 10512: 10509: 10505: 10501: 10496: 10494: 10490: 10483: 10482: 10474: 10472: 10468: 10456: 10450: 10447: 10443: 10439: 10434: 10429: 10422: 10421: 10413: 10410: 10398: 10392: 10389: 10386: 10381:on 2004-08-23 10380: 10376: 10370: 10366: 10365: 10357: 10354: 10347: 10345: 10331: 10327: 10324: 10321: 10318: 10289: 10285: 10282: 10279: 10276: 10269: 10255: 10248: 10244: 10241: 10238: 10235: 10225: 10222: 10221: 10206: 10202: 10199: 10196: 10193: 10186: 10172: 10165: 10158: 10154: 10151: 10148: 10145: 10139: 10136: 10133: 10123: 10121: 10120: 10116: 10113: 10110: 10109: 10106: 10089: 10086: 10077: 10074: 10068: 10065: 10062: 10056:η-redex 10045: 10031: 10028: 10021: 10020: 10019: 10016: 10014: 10010: 10002: 9997: 9978: 9975: 9972: 9966: 9957: 9951: 9948: 9945: 9942: 9933: 9927: 9924: 9921: 9918: 9909: 9906: 9898: 9881: 9878: 9875: 9869: 9863: 9857: 9851: 9848: 9840: 9839: 9837: 9834: 9815: 9812: 9809: 9803: 9794: 9788: 9785: 9782: 9779: 9770: 9764: 9761: 9758: 9755: 9746: 9743: 9735: 9718: 9715: 9712: 9706: 9700: 9694: 9688: 9685: 9677: 9676: 9674: 9673: 9672: 9645: 9639: 9633: 9630: 9618: 9612: 9609: 9606: 9603: 9594: 9588: 9585: 9582: 9579: 9560: 9554: 9548: 9545: 9533: 9527: 9524: 9521: 9518: 9509: 9503: 9500: 9497: 9494: 9477: 9476: 9470: 9443: 9437: 9434: 9425: 9422: 9419: 9410: 9404: 9401: 9392: 9389: 9386: 9377: 9374: 9371: 9368: 9362: 9352: 9349: 9348: 9324: 9318: 9315: 9306: 9303: 9300: 9291: 9285: 9282: 9273: 9270: 9267: 9258: 9255: 9252: 9249: 9243: 9233: 9230: 9229: 9226: 9203: 9197: 9191: 9185: 9182: 9179: 9170: 9164: 9158: 9152: 9149: 9146: 9137: 9134: 9131: 9128: 9125: 9122: 9112: 9109: 9108: 9105: 9085: 9082: 9067: 9064: 9061: 9058: 9055: 9052: 9043: 9040: 9037: 9034: 9031: 9028: 9022: 9019: 9016: 9010: 9007: 9004: 9001: 8995: 8985: 8965: 8959: 8947: 8941: 8938: 8935: 8932: 8923: 8917: 8914: 8911: 8908: 8902: 8899: 8896: 8890: 8887: 8884: 8881: 8878: 8875: 8865: 8863: 8860: 8859: 8855: 8828: 8820: 8815: 8806: 8803: 8800: 8791: 8785: 8780: 8772: 8769: 8766: 8757: 8754: 8751: 8748: 8742: 8732: 8729: 8728: 8704: 8696: 8691: 8682: 8679: 8676: 8667: 8661: 8648: 8645: 8642: 8633: 8630: 8627: 8624: 8618: 8608: 8605: 8604: 8601: 8578: 8572: 8566: 8560: 8557: 8554: 8545: 8539: 8533: 8527: 8524: 8521: 8512: 8509: 8506: 8503: 8500: 8497: 8487: 8484: 8483: 8479: 8459: 8456: 8441: 8438: 8435: 8432: 8429: 8426: 8417: 8414: 8411: 8408: 8405: 8402: 8396: 8393: 8390: 8384: 8381: 8378: 8375: 8369: 8359: 8339: 8333: 8321: 8315: 8312: 8309: 8306: 8297: 8291: 8288: 8285: 8282: 8276: 8273: 8270: 8264: 8261: 8258: 8255: 8252: 8249: 8239: 8237: 8236: 8232: 8229: 8227:λ-expression 8226: 8223: 8222: 8219: 8218:See example; 8216: 8202: 8195:but bound in 8182: 8162: 8136: 8133: 8130: 8124: 8121: 8115: 8109: 8106: 8103: 8100: 8094: 8050: 8044: 8041: 8038: 8035: 8032: 8026: 8020: 8017: 8014: 8011: 8008: 8005: 7992: 7991: 7990: 7988: 7984: 7979: 7973: 7967:is captured. 7954: 7947: 7930: 7925: 7917: 7914: 7911: 7908: 7902: 7895: 7878: 7872: 7866: 7863: 7860: 7857: 7854: 7851: 7844: 7826: 7820: 7814: 7811: 7808: 7800: 7799: 7795: 7778: 7775: 7766: 7763: 7760: 7757: 7751: 7744: 7727: 7721: 7715: 7712: 7709: 7706: 7703: 7700: 7693: 7690: 7689: 7685: 7668: 7665: 7656: 7653: 7650: 7647: 7641: 7634: 7617: 7611: 7605: 7602: 7599: 7596: 7593: 7590: 7583: 7581: 7580: 7576: 7573: 7571:λ-expression 7570: 7568:α-conversion 7567: 7566: 7563: 7562:See example; 7560: 7546: 7520: 7514: 7473: 7470: 7467: 7461: 7458: 7455: 7452: 7449: 7443: 7440: 7437: 7434: 7428: 7425: 7419: 7413: 7410: 7407: 7404: 7394: 7393: 7392: 7390: 7385: 7383: 7367: 7364: 7361: 7358: 7338: 7335: 7332: 7329: 7317: 7315: 7313: 7309: 7304: 7302: 7294: 7290: 7287: 7284: 7280: 7277: 7274: 7270: 7267: 7266: 7265: 7262: 7256: 7237: 7231: 7228: 7225: 7222: 7216: 7210: 7207: 7204: 7195: 7189: 7186: 7183: 7180: 7170: 7169: 7168: 7148: 7142: 7139: 7136: 7133: 7127: 7121: 7118: 7115: 7106: 7100: 7097: 7094: 7091: 7081: 7080: 7079: 7076: 7056: 7053: 7050: 7044: 7041: 7038: 7035: 7032: 7026: 7023: 7020: 7011: 7008: 7005: 7002: 6990: 6987: 6984: 6977: 6963: 6960: 6957: 6954: 6951: 6945: 6942: 6939: 6930: 6927: 6924: 6921: 6911: 6910: 6909: 6889: 6886: 6883: 6877: 6874: 6871: 6868: 6865: 6859: 6856: 6853: 6844: 6841: 6838: 6835: 6825: 6824: 6823: 6821: 6813: 6811: 6795: 6789: 6786: 6783: 6780: 6771: 6768: 6765: 6762: 6742: 6736: 6730: 6727: 6724: 6721: 6712: 6710: 6706: 6701: 6698: 6692: 6690: 6687: 6683: 6681: 6673: 6657: 6654: 6648: 6642: 6639: 6632: 6631: 6630: 6606: 6600: 6597: 6594: 6592: 6584: 6578: 6572: 6569: 6562: 6559: 6557: 6546: 6540: 6534: 6531: 6528: 6522: 6519: 6512: 6509: 6507: 6499: 6490: 6487: 6484: 6481: 6472: 6469: 6458: 6457: 6456: 6453: 6447: 6431: 6428: 6422: 6416: 6413: 6406: 6405: 6404: 6380: 6374: 6371: 6368: 6362: 6356: 6353: 6350: 6348: 6340: 6334: 6328: 6325: 6318: 6315: 6313: 6302: 6296: 6290: 6287: 6284: 6278: 6275: 6268: 6265: 6263: 6255: 6246: 6243: 6240: 6237: 6228: 6225: 6214: 6213: 6212: 6206: 6204: 6182: 6179: 6177: 6172: 6165: 6162: 6160: 6155: 6144: 6143: 6142: 6118: 6112: 6109: 6106: 6104: 6096: 6090: 6087: 6080: 6077: 6075: 6067: 6061: 6058: 6051: 6048: 6046: 6038: 6032: 6029: 6013: 6007: 6001: 5998: 5995: 5989: 5954: 5951: 5948: 5946: 5935: 5929: 5923: 5920: 5917: 5911: 5908: 5896: 5893: 5891: 5883: 5877: 5874: 5864: 5861: 5855: 5846: 5843: 5840: 5837: 5828: 5790: 5787: 5784: 5782: 5774: 5765: 5762: 5759: 5756: 5747: 5744: 5728: 5722: 5719: 5710: 5704: 5701: 5695: 5692: 5686: 5683: 5680: 5678: 5670: 5664: 5658: 5655: 5644: 5643: 5642: 5640: 5636: 5611: 5608: 5605: 5599: 5596: 5590: 5587: 5580: 5579: 5578: 5576: 5571: 5567: 5560: 5555: 5551: 5548: 5544: 5543: 5542: 5534: 5517: 5503: 5497: 5483: 5477: 5471: 5453: 5450: 5433: 5419: 5413: 5399: 5393: 5387: 5369: 5368: 5364: 5347: 5341: 5335: 5321: 5315: 5312: 5309: 5306: 5288: 5285: 5268: 5256: 5242: 5236: 5233: 5230: 5227: 5209: 5208: 5204: 5187: 5181: 5163: 5160: 5143: 5137: 5131: 5113: 5112: 5108: 5090: 5072: 5069: 5051: 5033: 5032: 5029: 5026: 5024: 5019: 5016: 5008: 5006: 5004: 4985: 4982: 4976: 4973: 4970: 4961: 4952: 4949: 4946: 4939: 4925: 4922: 4916: 4913: 4910: 4901: 4892: 4889: 4886: 4879: 4862: 4859: 4856: 4850: 4843: 4840: 4837: 4831: 4828: 4822: 4819: 4816: 4807: 4803: 4793: 4776: 4773: 4770: 4764: 4761: 4758: 4755: 4752: 4746: 4743: 4740: 4731: 4728: 4725: 4722: 4712: 4711: 4710: 4693: 4690: 4687: 4681: 4669: 4650: 4644: 4641: 4635: 4626: 4623: 4620: 4614: 4608: 4605: 4602: 4595: 4581: 4578: 4572: 4563: 4560: 4557: 4551: 4544: 4530: 4527: 4521: 4515: 4508: 4507: 4506: 4501:Map operators 4500: 4498: 4471: 4465: 4459: 4456: 4453: 4451: 4443: 4440: 4437: 4434: 4431: 4425: 4422: 4412: 4409: 4406: 4403: 4400: 4397: 4394: 4388: 4385: 4376: 4373: 4370: 4367: 4364: 4361: 4358: 4352: 4349: 4346: 4344: 4336: 4333: 4330: 4327: 4324: 4318: 4312: 4309: 4299: 4296: 4293: 4290: 4284: 4281: 4278: 4272: 4269: 4266: 4260: 4257: 4254: 4248: 4242: 4239: 4236: 4233: 4231: 4223: 4220: 4217: 4214: 4211: 4208: 4205: 4202: 4196: 4193: 4183: 4180: 4177: 4174: 4171: 4165: 4162: 4159: 4157: 4149: 4146: 4143: 4137: 4134: 4123: 4122: 4121: 4115: 4113: 4110: 4108: 4088: 4065: 4059: 4056: 4049: 4046: 4031: 4011: 3991: 3968: 3965: 3962: 3956: 3948: 3945: 3942: 3939: 3938: 3937: 3920: 3917: 3908: 3902: 3896: 3893: 3890: 3884: 3846: 3840: 3837: 3834: 3831: 3823: 3806: 3803: 3800: 3794: 3791: 3785: 3779: 3776: 3773: 3770: 3764: 3724: 3707: 3704: 3698: 3692: 3686: 3683: 3680: 3674: 3671: 3668: 3662: 3659: 3650: 3644: 3604: 3603: 3602: 3596: 3594: 3587: 3582: 3579: 3576: 3575: 3574: 3557: 3554: 3551: 3548: 3545: 3542: 3539: 3536: 3533: 3530: 3527: 3524: 3521: 3518: 3511: 3510: 3509: 3492: 3483: 3477: 3471: 3468: 3462: 3456: 3449: 3448: 3447: 3427: 3421: 3415: 3412: 3409: 3406: 3403: 3397: 3394: 3391: 3388: 3381: 3380: 3379: 3376: 3265: 3256:variable-list 3224:variable-list 3217: 3209: 3180: 3177: 3176: 3172: 3145: 3142: 3141: 3138: 3111: 3108: 3107: 3103: 3067: 3064: 3063: 3060: 3033: 3030: 3029: 3025: 3007:variable-list 2987: 2984: 2983: 2979: 2976: 2973: 2972: 2969: 2963: 2956: 2953: 2952: 2948: 2945: 2944: 2940: 2937: 2936: 2932: 2929: 2928: 2925: 2924:for details. 2923: 2917: 2913: 2906:Normalization 2905: 2903: 2889: 2869: 2849: 2826: 2823: 2817: 2814: 2811: 2803: 2799: 2791: 2789: 2775: 2772: 2769: 2760: 2751: 2748: 2745: 2739: 2736: 2733: 2707: 2704: 2701: 2698: 2695: 2686: 2668: 2665: 2661: 2658: 2652: 2628: 2625: 2615: 2612: 2609: 2606: 2588: 2586: 2569: 2566: 2563: 2560: 2537: 2514: 2511: 2508: 2505: 2495:to result in 2479: 2476: 2473: 2464: 2461: 2458: 2455: 2422: 2416: 2413: 2410: 2407: 2399: 2396: 2393: 2379: 2376: 2373: 2367: 2361: 2358: 2355: 2352: 2350: 2342: 2339: 2336: 2327: 2324: 2321: 2318: 2308: 2305: 2302: 2299: 2296: 2294: 2286: 2283: 2280: 2271: 2268: 2265: 2262: 2246: 2243: 2240: 2232: 2228: 2212: 2209: 2206: 2198: 2194: 2187: 2185: 2177: 2174: 2171: 2160: 2156: 2147: 2143: 2128: 2127: 2108: 2105: 2102: 2094: 2091: 2089: 2081: 2078: 2075: 2069: 2062: 2059: 2057: 2049: 2046: 2043: 2037: 2026: 2025: 2024: 2010: 1990: 1970: 1947: 1944: 1941: 1935: 1923: 1921: 1919: 1915: 1911: 1907: 1902: 1888: 1885: 1882: 1879: 1876: 1873: 1870: 1850: 1847: 1844: 1841: 1838: 1835: 1832: 1812: 1792: 1783: 1769: 1766: 1763: 1760: 1757: 1754: 1751: 1743: 1727: 1724: 1721: 1718: 1715: 1712: 1709: 1689: 1686: 1683: 1680: 1677: 1674: 1671: 1661: 1659: 1643: 1640: 1637: 1634: 1614: 1611: 1608: 1605: 1593: 1591: 1577: 1554: 1551: 1548: 1542: 1522: 1516: 1513: 1510: 1507: 1487: 1467: 1447: 1427: 1407: 1387: 1378: 1375: 1372: 1369: 1358: 1354: 1349: 1347: 1339: 1335: 1332: 1329: 1325: 1322: 1319: 1315: 1312: 1311: 1310: 1307: 1301: 1299: 1297: 1293: 1271: 1265: 1262: 1259: 1253: 1247: 1244: 1241: 1235: 1229: 1223: 1220: 1213: 1196: 1184: 1178: 1175: 1172: 1166: 1163: 1160: 1157: 1151: 1148: 1141: 1139:is a variable 1126: 1103: 1097: 1091: 1085: 1082: 1075: 1074: 1073: 1056: 1050: 1047: 1027: 1019: 1014: 998: 992: 989: 986: 983: 977: 974: 971: 968: 948: 928: 922: 916: 913: 910: 907: 887: 867: 859: 855: 839: 827: 811: 808: 805: 802: 799: 796: 776: 773: 770: 767: 764: 761: 758: 755: 752: 749: 741: 727: 718: 715: 712: 709: 683: 677: 671: 668: 665: 645: 639: 636: 633: 630: 622: 618: 601: 592: 586: 560: 554: 548: 540: 523: 517: 494: 488: 480: 479: 478: 472: 470: 450: 444: 438: 412: 409: 406: 403: 395: 378: 372: 369: 366: 363: 337: 334: 314: 306: 289: 286: 266: 258: 257: 256: 254: 226: 224:' and dot '.' 211: 203: 186: 182: 159: 155: 132: 128: 119: 118: 117: 111: 109: 107: 106:Alonzo Church 99: 97: 95: 84: 81: 73: 70:November 2014 63: 59: 53: 50:This article 48: 39: 38: 33: 19: 10575: 10569: 10558:. Retrieved 10554: 10545: 10527: 10510: 10507: 10480: 10459:. Retrieved 10449: 10419: 10412: 10401:. Retrieved 10391: 10379:the original 10363: 10356: 10306: 10117:β-reduction 10104: 10017: 10006: 9670: 8861: 8224:β-reduction 8217: 8154: 7980: 7977: 7561: 7538: 7386: 7382:α-equivalent 7381: 7321: 7318:α-conversion 7311: 7310:, short for 7307: 7305: 7301:β-equivalent 7300: 7298: 7292: 7288: 7282: 7278: 7272: 7269:α-conversion 7268: 7263: 7260: 7166: 7077: 7074: 6907: 6817: 6713: 6708: 6704: 6702: 6699: 6696: 6688: 6684: 6677: 6628: 6454: 6451: 6402: 6210: 6201: 6140: 5638: 5634: 5632: 5574: 5572: 5568: 5564: 5540: 5027: 5022: 5020: 5014: 5012: 5000: 4673: 4504: 4496: 4119: 4111: 4104: 3935: 3600: 3591: 3572: 3507: 3445: 3377: 3374: 3263: 3215: 2980:Description 2967: 2933:Definition. 2918: 2915: 2795: 2687: 2592: 2444: 1927: 1924:Substitution 1903: 1784: 1741: 1662: 1658:α-equivalent 1657: 1627:might yield 1597: 1594:α-conversion 1356: 1355:, short for 1352: 1350: 1346:β-equivalent 1345: 1343: 1337: 1333: 1327: 1323: 1317: 1314:α-conversion 1313: 1308: 1305: 1291: 1289: 1017: 1015: 857: 853: 831: 476: 468: 230: 115: 103: 91: 76: 67: 51: 10385:Corrections 10003:η-reduction 7351:might give 7289:η-reduction 7279:β-reduction 6207:Normal form 5021:The set of 5013:The set of 4107:normal form 3065:Application 2985:Abstraction 2938:Normal Form 2792:η-reduction 2589:β-reduction 1334:η-reduction 1324:β-reduction 1016:The set of 507:instead of 10560:2024-05-14 10508:Dialectica 10461:2012-06-18 10403:2012-06-18 10348:References 9231:Canonical 8606:Canonical 6822:the rule, 3200:expression 3040:expression 3017:expression 2994:expression 2390:, if  2099:, if  1744:result in 120:variables 112:Definition 10433:0804.3434 10319:λ 10277:λ 10236:λ 10194:λ 10146:λ 10134:λ 10111:Reduction 10063:λ 10052:→ 9943:λ 9919:λ 9910:⁡ 9852:⁡ 9780:λ 9756:λ 9747:⁡ 9689:⁡ 9604:λ 9580:λ 9519:λ 9495:λ 9435:⁡ 9420:λ 9402:⁡ 9387:λ 9372:λ 9363:λ 9316:⁡ 9301:λ 9283:⁡ 9268:λ 9253:λ 9244:λ 9180:λ 9147:λ 9132:λ 9123:λ 9083:⁡ 9065:⁡ 9053:λ 9041:⁡ 9029:λ 9017:λ 9005:λ 8996:λ 8933:λ 8909:λ 8897:λ 8885:λ 8876:λ 8816:⁡ 8801:λ 8767:λ 8752:λ 8743:λ 8692:⁡ 8677:λ 8643:λ 8628:λ 8619:λ 8555:λ 8522:λ 8507:λ 8498:λ 8457:⁡ 8439:⁡ 8427:λ 8415:⁡ 8403:λ 8391:λ 8379:λ 8370:λ 8307:λ 8283:λ 8271:λ 8259:λ 8250:λ 8101:λ 8095:⁡ 8060:→ 8033:∨ 8003:∀ 7912:λ 7903:λ 7861:λ 7852:λ 7809:λ 7776:⁡ 7761:λ 7752:λ 7710:λ 7701:λ 7666:⁡ 7651:λ 7642:λ 7600:λ 7591:λ 7515:⁡ 7483:→ 7453:λ 7435:λ 7426:∧ 7359:λ 7330:λ 7306:The term 7223:λ 7181:λ 7134:λ 7092:λ 7036:λ 7003:λ 6997:→ 6988:≠ 6955:λ 6922:λ 6869:λ 6836:λ 6781:λ 6763:λ 6722:λ 6643:⁡ 6601:⁡ 6573:⁡ 6529:λ 6523:⁡ 6482:λ 6473:⁡ 6417:⁡ 6375:⁡ 6369:∧ 6357:⁡ 6329:⁡ 6285:λ 6279:⁡ 6238:λ 6229:⁡ 6113:⁡ 6091:⁡ 6062:⁡ 6033:⁡ 5996:λ 5990:⁡ 5955:⁡ 5918:λ 5912:⁡ 5878:⁡ 5838:λ 5829:⁡ 5791:⁡ 5757:λ 5748:⁡ 5723:⁡ 5705:⁡ 5696:⁡ 5687:⁡ 5659:⁡ 5600:⁡ 5591:⁡ 5504:∪ 5420:∪ 5342:∪ 5307:λ 5263:∖ 5228:λ 5191:∅ 4956:→ 4950:≠ 4896:→ 4756:λ 4723:λ 4612:→ 4606:≠ 4460:⁡ 4426:⁡ 4389:⁡ 4353:⁡ 4313:⁡ 4261:⁡ 4243:⁡ 4237:λ 4203:λ 4197:⁡ 4166:⁡ 4138:⁡ 4060:⁡ 3891:λ 3885:⁡ 3853:→ 3841:⁡ 3771:λ 3765:⁡ 3687:⁡ 3663:⁡ 3657:→ 3645:⁡ 3597:Semantics 3549:λ 3540:λ 3519:λ 3410:λ 3389:λ 3335:extension 3314:extension 3302:extension 3293:extension 2862:whenever 2812:λ 2773:× 2767:→ 2749:× 2734:λ 2708:× 2607:λ 2561:λ 2506:λ 2456:λ 2411:∉ 2397:≠ 2356:λ 2353:≡ 2319:λ 2300:λ 2297:≡ 2263:λ 2188:≡ 2106:≠ 2092:≡ 2060:≡ 1880:λ 1871:λ 1863:, we get 1842:λ 1833:λ 1761:λ 1752:λ 1719:λ 1710:λ 1681:λ 1672:λ 1635:λ 1606:λ 1508:λ 1370:λ 1351:The term 1302:Reduction 1266:⁡ 1260:∪ 1248:⁡ 1224:⁡ 1191:∖ 1179:⁡ 1158:λ 1152:⁡ 1086:⁡ 1051:⁡ 984:λ 969:λ 908:λ 900:is free: 840:λ 797:λ 768:λ 759:λ 750:λ 710:λ 666:λ 631:λ 454:Λ 451:∈ 416:Λ 413:∈ 382:Λ 379:∈ 364:λ 341:Λ 338:∈ 293:Λ 290:∈ 251:, can be 239:Λ 212:λ 10600:Category 10383:— 10032:∉ 9350:Natural 9110:Beta 2, 8730:Natural 8233:Comment 8039:∉ 8015:∉ 7577:Comment 7408:∉ 6173:strategy 6156:strategy 5720:strategy 5109:Comment 5070:Comment 3835:∉ 3272:variable 3246:variable 3236:variable 3178:Grouping 3164:variable 3143:Variable 2669:′ 2629:′ 1119:, where 699:and not 473:Notation 10438:Bibcode 5788:canonym 5597:canonym 5554:β-redex 5541:Usage; 4423:canonym 4386:canonym 4350:canonym 4310:canonym 4258:canonym 4194:canonym 4163:canonym 4135:canonym 3941:canonym 3936:where, 3684:canonym 3660:canonym 3573:where, 428:, then 353:, then 174:, ..., 56:Please 10582:  10534:  10371:  9955:  9931:  9861:  9792:  9768:  9698:  9643:  9616:  9592:  9558:  9531:  9507:  9195:  9162:  8963:  8945:  8921:  8570:  8537:  8337:  8319:  8295:  8113:  7876:  7824:  7725:  7615:  7235:  7193:  7146:  7104:  6994:  6793:  6775:  6740:  6734:  6582:  6544:  6497:  6414:normal 6372:normal 6354:normal 6338:  6326:normal 6300:  6276:normal 6253:  6226:normal 6011:  5933:  5853:  5772:  5717:  5668:  5633:where 5475:  5391:  4383:  4322:  3906:  3783:  3490:  3481:  3466:  3460:  3425:  3401:  2758:  2743:  2622:  2222:  2153:  1520:  1385:  1292:closed 1233:  996:  926:  920:  725:  681:  658:means 643:  599:  590:  558:  552:  521:  492:  442:  10485:(PDF) 10428:arXiv 10424:(PDF) 9068:PNFNS 9056:PNFNS 9044:PNFNF 9032:PNFNF 8442:PNFNS 8430:PNFNS 8418:PNFNF 8406:PNFNF 7987:bound 7308:redex 7273:alpha 6705:bound 6563:false 6513:false 6319:false 6269:false 6183:eager 6088:eager 5875:apply 5745:apply 5693:apply 3366:digit 3356:alpha 3284:alpha 1916:(see 1914:scope 1910:masks 1805:with 1460:; if 1353:redex 1318:alpha 854:bound 201:, ... 10580:ISBN 10532:ISBN 10369:ISBN 10311:in 7983:free 7283:beta 6709:free 6658:true 6640:whnf 6598:whnf 6570:whnf 6520:whnf 6470:whnf 6432:true 6166:lazy 6110:eval 6059:lazy 6030:eval 5952:eval 5909:eval 5702:eval 5684:eval 5656:eval 5639:eval 5588:eval 5577:is, 4457:name 4240:name 3371:| _ 3369:> 3363:< 3359:> 3353:< 3347:> 3341:< 3338:> 3332:< 3329:> 3323:< 3317:> 3311:< 3305:> 3299:< 3296:> 3290:< 3287:> 3281:< 3275:> 3269:< 3259:> 3253:< 3249:> 3243:< 3239:> 3233:< 3227:> 3221:< 3203:> 3197:< 3190:> 3187:item 3184:< 3167:> 3161:< 3155:> 3152:item 3149:< 3133:> 3130:item 3127:< 3121:> 3115:< 3109:Item 3098:> 3095:item 3092:< 3089:> 3083:< 3077:> 3071:< 3055:> 3049:< 3043:> 3037:< 3020:> 3014:< 3010:> 3004:< 2997:> 2991:< 2974:Name 2842:and 1570:and 1420:for 1328:beta 858:free 10506:" 9444:PNS 9423:PNS 9411:PNF 9390:PNF 9325:PNS 9304:PNS 9292:PNF 9271:PNF 9062:PNF 9038:PNF 9020:PNF 8829:PNS 8821:PNS 8804:PNS 8792:PNF 8781:PNF 8770:PNF 8705:PNS 8680:PNS 8668:PNF 8646:PNF 8436:PNF 8412:PNF 8394:PNF 7293:eta 3350:::= 3320:::= 3308:::= 3278:::= 3230:::= 3193:::= 3158:::= 3124:::= 3080:::= 3046:::= 3000:::= 2977:BNF 2645:is 1920:). 1825:in 1742:not 1440:in 1338:eta 396:If 307:If 259:If 60:to 10602:: 10553:. 10518:^ 10511:42 10492:^ 10470:^ 10436:, 9907:BV 9849:FV 9744:BV 9686:FV 9634::= 9549::= 9438:PN 9405:PN 9375:PN 9319:PN 9286:PN 9256:PN 9086:PN 9008:PN 8786:PN 8755:PN 8697:PN 8662:PN 8631:PN 8460:PN 8382:PN 8134::= 7931:PN 7926:PN 7915:PN 7842:) 7779:PN 7764:PN 7669:PN 7654:PN 7471::= 7391:. 7384:. 7295:). 7275:); 7208::= 7119::= 7054::= 7024::= 6943::= 6887::= 6857::= 6711:. 6682:. 5005:. 4974::= 4914::= 4860::= 4841::= 4820::= 4774::= 4744::= 4691::= 4624::= 4561::= 4282::= 4109:. 4057:FV 3966::= 3949:, 3838:FV 3804::= 3361:| 3251:, 3241:| 3205:) 3195:( 3012:. 3002:λ 2902:. 2788:. 2685:. 2662::= 2477::= 2377::= 2340::= 2284::= 2244::= 2210::= 2175::= 2079::= 2047::= 1945::= 1590:. 1552::= 1500:, 1340:). 1330:); 1320:); 1298:. 1263:FV 1245:FV 1221:FV 1176:FV 1149:FV 1083:FV 1048:FV 623:: 255:: 147:, 108:. 10588:. 10563:. 10502:" 10464:. 10440:: 10430:: 10406:. 10332:x 10328:y 10325:. 10322:y 10309:x 10290:x 10286:a 10283:. 10280:a 10256:a 10252:) 10249:x 10245:y 10242:. 10239:y 10233:( 10207:a 10203:a 10200:. 10197:a 10173:a 10169:) 10166:x 10162:) 10159:x 10155:y 10152:. 10149:y 10143:( 10140:. 10137:x 10131:( 10090:f 10087:= 10084:] 10081:) 10078:x 10075:f 10072:( 10069:. 10066:x 10060:[ 10049:) 10046:f 10043:( 10039:V 10036:F 10029:x 9982:} 9979:b 9976:, 9973:a 9970:{ 9967:= 9964:) 9961:) 9958:b 9952:z 9949:. 9946:b 9940:( 9937:) 9934:a 9928:z 9925:. 9922:a 9916:( 9913:( 9885:} 9882:y 9879:, 9876:x 9873:{ 9870:= 9867:) 9864:y 9858:x 9855:( 9819:} 9816:y 9813:, 9810:x 9807:{ 9804:= 9801:) 9798:) 9795:y 9789:z 9786:. 9783:y 9777:( 9774:) 9771:x 9765:z 9762:. 9759:x 9753:( 9750:( 9722:} 9719:y 9716:, 9713:x 9710:{ 9707:= 9704:) 9701:y 9695:x 9692:( 9652:] 9649:) 9646:y 9640:x 9637:( 9631:z 9628:[ 9625:) 9622:) 9619:b 9613:z 9610:. 9607:b 9601:( 9598:) 9595:a 9589:z 9586:. 9583:a 9577:( 9574:( 9567:] 9564:) 9561:y 9555:x 9552:( 9546:z 9543:[ 9540:) 9537:) 9534:y 9528:z 9525:. 9522:y 9516:( 9513:) 9510:x 9504:z 9501:. 9498:x 9492:( 9489:( 9453:) 9450:) 9447:) 9441:) 9432:P 9429:( 9426:. 9417:( 9414:) 9408:) 9399:P 9396:( 9393:. 9384:( 9381:( 9378:. 9369:. 9366:P 9360:( 9334:) 9331:) 9328:) 9322:) 9313:P 9310:( 9307:. 9298:( 9295:) 9289:) 9280:P 9277:( 9274:. 9265:( 9262:( 9259:. 9250:. 9247:P 9241:( 9213:) 9210:) 9207:) 9204:b 9201:) 9198:y 9192:x 9189:( 9186:. 9183:b 9177:( 9174:) 9171:a 9168:) 9165:y 9159:x 9156:( 9153:. 9150:a 9144:( 9141:( 9138:. 9135:y 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3795:b 3792:= 3789:] 3786:v 3780:b 3777:. 3774:p 3768:[ 3761:x 3758:e 3755:d 3752:e 3749:r 3746:- 3743:a 3740:t 3737:e 3734:b 3711:] 3708:P 3705:, 3702:] 3699:A 3696:[ 3693:a 3690:[ 3681:= 3678:] 3675:P 3672:, 3669:A 3666:[ 3654:) 3651:a 3648:( 3641:v 3638:n 3635:o 3632:c 3629:- 3626:a 3623:h 3620:p 3617:l 3614:a 3558:z 3555:. 3552:y 3546:. 3543:x 3537:= 3534:z 3531:. 3528:y 3525:. 3522:x 3493:z 3487:) 3484:y 3478:x 3475:( 3472:= 3469:z 3463:y 3457:x 3431:) 3428:z 3422:y 3419:( 3416:. 3413:x 3407:= 3404:z 3398:y 3395:. 3392:x 2890:f 2870:x 2850:f 2830:) 2827:x 2824:f 2821:( 2818:. 2815:x 2776:2 2770:7 2764:) 2761:7 2755:) 2752:2 2746:n 2740:. 2737:n 2731:( 2728:( 2705:, 2702:7 2699:, 2696:2 2673:] 2666:E 2659:V 2656:[ 2653:E 2633:) 2626:E 2619:) 2616:E 2613:. 2610:V 2604:( 2601:( 2573:) 2570:x 2567:. 2564:z 2558:( 2538:x 2518:) 2515:x 2512:. 2509:x 2503:( 2483:] 2480:x 2474:y 2471:[ 2468:) 2465:y 2462:. 2459:x 2453:( 2426:) 2423:N 2420:( 2417:V 2414:F 2408:y 2400:y 2394:x 2386:) 2383:] 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Index

Weak head normal form
Lambda calculus
help improve it
make it understandable to non-experts
Learn how and when to remove this message
function application
Alonzo Church
defined inductively
as far right as possible
combinatory logic
name resolution
masks
scope
alpha renaming to make name resolution trivial
extensionality
if and only if
Beta normal form
Beta normal form
canonym
Substitution Operator
Free Variable Set
normal form
Changes to the substitution operator
definition of the η-reduction
β-redex
definition as mathematical formulas
Substitution Operator
free variables
free
bound

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