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Combinatory logic

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1334:, we would have to resort to our knowledge of multiplication and the number 3. Since any computation is simply a composition of the evaluation of suitable functions on suitable primitive arguments, this simple substitution principle suffices to capture the essential mechanism of computation. Moreover, in lambda calculus, notions such as '3' and ' 4620:
The undecidable problems above (equivalence, existence of normal form, etc.) take as input syntactic representations of terms under a suitable encoding (e.g., Church encoding). One may also consider a toy trivial computation model where we "compute" properties of terms by means of combinators applied
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is any combinatory term in which the primitive combinators that occur, if any, are not applied to enough arguments to be simplified. It is undecidable whether a general combinatory term has a normal form; whether two combinatory terms are equivalent, etc. This can be shown in a similar way as for the
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However, note that it also immediately follows from this undefinability theorem that many properties of terms that are obviously decidable are not definable by complete predicates either: e.g., there is no predicate that could tell whether the first primitive function letter occurring in a term is a
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is a model of computation equivalent to lambda calculus, but without abstraction. The advantage of this is that evaluating expressions in lambda calculus is quite complicated because the semantics of substitution must be specified with great care to avoid variable capture problems. In contrast,
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It is perhaps surprising that lambda-calculus can represent any conceivable computation using only the simple notions of function abstraction and application based on simple textual substitution of terms for variables. But even more remarkable is that abstraction is not even required.
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Since abstraction is the only way to manufacture functions in the lambda calculus, something must replace it in the combinatory calculus. Instead of abstraction, combinatory calculus provides a limited set of primitive functions out of which other functions may be built.
1358:' can be represented without any need for externally defined primitive operators or constants. It is possible to identify terms in lambda calculus, which, when suitably interpreted, behave like the number 3 and like the multiplication operator, q.v. 146:, which proved more popular than combinatory logic. The upshot of these historical contingencies was that until theoretical computer science began taking an interest in combinatory logic in the 1960s and 1970s, nearly all work on the subject was by 2794:
It is rules 5 and 6 that are of interest. Rule 5 simply says that to convert a complex abstraction to a combinator, we must first convert its body to a combinator, and then eliminate the abstraction. Rule 6 actually eliminates the abstraction.
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as given is not a well-typed mathematical function, but rather a term rewriter: Although it eventually yields a combinator, the transformation may generate intermediary expressions that are neither lambda terms nor combinators, via rule (5).
5087:, that is, programming in functional expressions containing no variables, along with powerful tools for working with such programs. It turns out that tacit programming is possible in any APL-like language with user-defined operators. 2790:
The first two rules are also simple: Variables convert to themselves, and applications, which are allowed in combinatory terms, are converted to combinators simply by converting the applicand and the argument to combinators.
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From this undefinability theorem it immediately follows that there is no complete predicate that can discriminate between terms that have a normal form and terms that do not have a normal form. It also follows that there is
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The motivation for this definition of reduction is that it captures the essential behavior of all mathematical functions. For example, consider the function that computes the square of a number. We might write
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corresponds to a reduction of a typed lambda term, and conversely. Moreover, theorems can be identified with function type signatures. Specifically, a typed combinatory logic corresponds to a
4139: 1712: 212:. It is easy to transform lambda expressions into combinator expressions, and combinator reduction is much simpler than lambda reduction. Hence combinatory logic has been used to model some 4069: 1101: 5256: 1545: 971: 1615: 5326: 230:
Combinatory logic can be given a variety of interpretations. Many early papers by Curry showed how to translate axiom sets for conventional logic into combinatory logic equations.
227:, whose sole primitives are the S and K combinators augmented with character input/output. Although not a practical programming language, Unlambda is of some theoretical interest. 5497: 4101: 4029: 2035:
if they always produce the same results for the same arguments. In contrast, the terms themselves, together with the reduction of primitive combinators, capture the notion of
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Bracket abstraction induces a translation from lambda terms to combinator expressions, by interpreting lambda-abstractions using the bracket abstraction algorithm.
1140: 905: 874: 843: 804: 773: 742: 653: 622: 543: 457: 426: 6323: 1330: 1297: 1228: 1354: 1255: 1017: 395: 279: 162:(1972) survey the early history of combinatory logic. For a more modern treatment of combinatory logic and the lambda calculus together, see the book by 1369:); that is, any calculation that can be accomplished in any of these other models can be expressed in lambda calculus, and vice versa. According to the 6670: 4754:. An analogue of Rice's theorem for this toy model then says that every complete predicate is trivial. The proof of this theorem is rather simple. 3732:
These combinators are extremely useful when translating predicate logic or lambda calculus into combinator expressions. They were also used by
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of the function. To evaluate the square for a particular argument, say 3, we insert it into the definition in place of the formal parameter:
6482: 6656: 6379:]. From Frege to Gödel: A Source Book in Mathematical Logic, 1879-1931. Translated by Bauer-Mengelberg, Stefan. Cambridge, MA, USA: 108: 6754: 6499: 6468: 6388: 3740:, whose name has been associated with their computational use. Using them, we can extend the rules for the transformation as follows: 209: 6597: 6546: 6439: 6309: 6205: 6102: 6061: 6035: 5942: 3737: 6689: 5934: 4608: 2101:
lambda term, and therefore, by Church's thesis, to any computable function whatsoever. The proof is to present a transformation,
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in 1920 with the idea of providing an analogous way to build up functions—and to remove any mention of variables—particularly in
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Lambda calculus is known to be computationally equivalent in power to many other plausible models for computation (including
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holds. A very simple algorithm for bracket abstraction is defined by induction on the structure of expressions as follows:
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built from variables and application and produces a combinator expression E in which the variable x is not free, such that
5725: 3094:₂), so the recursion must terminate in a lambda term with no applications at all—either a variable, or a term of the form 5096: 4294:
The reduction in combinator size that results from the new transformation rules can also be achieved without introducing
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A gentle introduction to combinatory logic, presented as a series of recreational puzzles using bird watching metaphors.
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is complete for the implicational fragment of the intuitionistic logic, which can be seen as follows. Consider the set
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directly to the terms themselves as arguments, rather than to their syntactic representations. More precisely, let a
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Chapters 17–20 are a more formal introduction to combinatory logic, with a special emphasis on fixed point results.
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transformation is motivated by a desire to eliminate abstraction. Two special cases, rules 3 and 4, are trivial:
1370: 6749: 6380: 6301: 1478: 6695: 6524: 2031:. Extensional equality captures the mathematical notion of the equality of functions: that two functions are 918: 4228:
takes a value and substitutes it into both the applicand and its argument before performing the application,
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evaluating expressions in combinatory logic is much simpler, because there is no notion of substitution.
6430: 5780: 5745: 81: 6072: 4002: 2508:(by feeding them in a queue-like fashion into the combinator 'from the right'), it reduces as follows: 6253: 6191: 5502: 6364: 6319: 5100: 4248: 2028: 556: 469: 289: 204:, in which lambda expressions (representing functional abstraction) are replaced by a limited set of 190: 135: 127: 85: 73: 61: 49: 5689: 5648: 5334: 4595:
Note, however, that this transformation is not the inverse transformation of any of the versions of
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The Lambda Calculus, Its Syntax and Semantics. Studies in Logic and the Foundations of Mathematics
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To Mock a Mockingbird And Other Logic Puzzles Including an Amazing Adventure in Combinatory Logic
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the expansion of primitive combinators. There are many ways to implement an identity function; (
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To Dissect a Mockingbird: A Graphical Notation for the Lambda Calculus with Animated Reduction.
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A celebration of the development of combinators, a hundred years after they were introduced by
5622: 5444: 5418: 6639: 6621: 6593: 6505: 6495: 6464: 6435: 6394: 6384: 6305: 6201: 6098: 6086: 6057: 6031: 5990:(1930). "Grundlagen der Kombinatorischen Logik" [Foundations of combinatorial logic]. 5965: 5938: 5764: 5730: 5532: 5084: 4244: 112: 100:
in logic, essentially by eliminating them. Another way of eliminating quantified variables is
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There are one-point bases from which every combinator can be composed extensionally equal to
1149: 197:. Despite its simplicity, combinatory logic captures many essential features of computation. 6664: 6558: 6452: 6425: 6338: 6249: 6228: 6187: 6151: 6133: 6121: 6049: 5999: 5957: 5570: 5366: 5259: 1264: 976: 513: 182: 57: 6171: 1113: 883: 852: 821: 782: 751: 720: 631: 600: 521: 435: 404: 6716: 6706: 6683: 6607: 6589:
Combinatory logic in programming: Computations with objects through examples and exercises
6167: 5926: 5775: 5760: 5052:. This shows that definability by predicates is a not a reasonable model of decidability. 4646: 1359: 247: 201: 163: 143: 96:
Combinatory logic was originally intended as a 'pre-logic' that would clarify the role of
77: 6217:"On the Complexity of the Standard Translation of Lambda Calculus into Combinatory Logic" 1309: 1276: 1207: 142:
and his students at Princeton invented a rival formalism for functional abstraction, the
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Goldberg, Mayer (2004). "A construction of one-point bases in extended lambda calculi".
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In combinatory logic, each primitive combinator comes with a reduction rule of the form
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combinator according to rules similar to those presented above for the conversion of λ
6738: 6617: 6490:. Studies in Logic and the Foundations of Mathematics. Vol. 149 (1st ed.). 6350: 6045: 6019: 5987: 4240: 3733: 1467: 147: 139: 131: 53: 6578: 6407: 5979: 6233: 6179: 5108: 3507: 715:. Applications model function invocation or execution: the function represented by 235: 194: 167: 591:
represents the function which, applied to an argument, binds the formal parameter
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implies a connection between logic and programming: every proof of a theorem of
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By reductio ad absurdum. Suppose there is a complete non trivial predicate, say
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is a variable name drawn from a predefined infinite set of variable names, and
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This definition obeys the conditions on satisfaction of →: on one hand, if
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and function application corresponds to the detachment (modus ponens) rule
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can be composed to produce combinators that are extensionally equal to
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and earlier defined combinators to define a result from its arguments.
6676: 6279: 4977: 6562: 6155: 6003: 4673:, transformed into combinatory logic; the combinatory versions have 3172:
Taking this simplification into account, the example above becomes:
1776:. It is in this way that primitive combinators behave as functions. 256:, which can be represented by the following three forms of strings: 6700: 6535: 5801:, The article that founded combinatory logic. English translation: 1456:
Applying a function to an argument. M and N are combinatory terms.
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to the old one. If a lambda term contains no subterms of the form
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The article that founded combinatory logic. English translation:
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itself is unnecessary, since it can be built from the other two:
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Proceedings of the international conference on APL '91 - APL '91
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Fixed point theorem gives: ABSURDUM = (NEGATION ABSURDUM), for
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transformation can be made smaller if we take into account the
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Conversion of a lambda term to an equivalent combinatorial term
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rediscovered the combinators while working as an instructor at
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He also explains how they in turn can be expressed using only
6686:" A table distilling much of the essence of Smullyan (1985). 2701:)) is much longer than the representation as a lambda term, 5678:
be any formula which is not provable in the calculus. Then
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calculus. The distinction corresponds to that between the λ
1466:, or functions that, when seen as lambda terms, contain no 223:. The purest form of this view is the programming language 6459:. Oxford logic guides. Vol. 27. Oxford and New York: 3226:
This combinator is equivalent to the earlier, longer one:
1855:. Or, following the convention for multiple application, 3041:₂), it is sufficient to find a combinator equivalent to ( 595:
to the argument and then computes the resulting value of
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Logical formalism using combinators instead of variables
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Cherlin, Edward (1991). "Pure functions in APL and J".
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of all deductively closed sets of formulas, ordered by
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To shorten the notations, a general convention is that
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A character or string representing a combinatory term.
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lambda term. The simplest example of such a basis is {
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devised for combinatory logic in the 1960s and 1970s.
6549:(1979). "Another Algorithm for Bracket Abstraction". 6534:. World Scientific Publishing Company. Archived from 5692: 5651: 5625: 5599: 5573: 5541: 5505: 5473: 5447: 5421: 5395: 5369: 5337: 5291: 5268: 5232: 5044:) would have to be a complete non trivial predicate. 4458:
from combinatorial terms to lambda terms is trivial:
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performs the substitution only in the applicand, and
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If we apply this combinatorial term to any two terms
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used primitives based on Curry's combinators in his
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is supposed to be non trivial there are combinators
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be a combinator that, when applied, returns either
1373:, both models can express any possible computation. 847:, the argument, may be substituted into the body of 200:
Combinatory logic can be viewed as a variant of the
6481:SĂžrensen, Morten Heine B; Urzyczyn, PaweƂ (2006) . 5065:David Turner used his combinators to implement the 3161:to it; this is extensionally equal to the function 1821:) is the function which, for any argument, returns 1399:A combinatory term has one of the following forms: 6532:Randomness And Complexity, from Leibniz To Chaitin 6090: 5998:(3). The Johns Hopkins University Press: 509–536. 5704: 5663: 5637: 5611: 5585: 5559: 5523: 5491: 5459: 5433: 5407: 5381: 5355: 5320: 5274: 5250: 4133: 4095: 4063: 4023: 1706: 1609: 1539: 1348: 1324: 1291: 1249: 1222: 1176: 1134: 1095: 1011: 965: 899: 868: 837: 798: 767: 736: 701: 647: 616: 581: 537: 494: 451: 420: 389: 362: 314: 273: 6300:(Enl. ed., 2. print ed.). Cambridge, Mass.: 6268:Proceedings of the American Philosophical Society 6138:"Principal type-schemes and condensed detachment" 4446:combinators. See chapter 9 in Barendregt (1984). 3576:In fact, there exist infinitely many such bases. 3342:transformation transformed the identity function 3086:₂ each contain strictly fewer applications than ( 1880:, which is a generalized version of application: 1758:is a term mentioning only variables from the set 252:Lambda calculus is concerned with objects called 6193:Lambda-Calculus and Combinators: An Introduction 4424:terms can be composed (modulo equality). Every λ 3517:Another simple example of a one-point basis is: 3029:Therefore, to find a combinator equivalent to 2713:construction may expand a lambda term of length 1707:{\displaystyle (...((E_{1}E_{2})E_{3})...E_{n})} 975:then it cannot be reduced, and is said to be in 777:as its argument, and the result is computed. If 6592:(2nd ed.). Moscow: "Center JurInfoR" Ltd. 5850: 4239:The modern names for the combinators come from 2246: 909:, and the result is a new lambda term which is 111:of combinatory logic typically exceeds that of 6525:"Binary Lambda Calculus and Combinatory Logic" 4064:{\displaystyle \mathbf {X} _{*}=\mathbf {XI} } 3596:included two combinators which are now called 3165:itself. It is therefore sufficient to convert 2849:is just the same as substituting it into both 2809:₂) is a function which takes an argument, say 6696:Binary Lambda Calculus and Combinatory Logic. 6324:"Über die Bausteine der mathematischen Logik" 2324:For example, we will convert the lambda term 1096:{\displaystyle ((\lambda v.E)a)\Rightarrow E} 8: 6377:On the building blocks of mathematical logic 5554: 5548: 5251:{\displaystyle \langle W,\subseteq \rangle } 5245: 5233: 4971:, which contradicts the presupposition that 3153:x) is the function which takes an argument, 2063:to indicate extensional equality, reserving 2043:only if they have identical implementations 126:The original inventor of combinatory logic, 6633: 6373:Über die Bausteine der mathematischen Logik 6356: 5802: 5798: 4975:would be a complete non trivial predicate. 4134:{\displaystyle \mathbf {X} '=\mathbf {CX} } 3593: 2813:, and substitutes it into the lambda term ( 2078:combinator, which can be used to implement 1814:, which manufactures constant functions: ( 234:in the 1960s and 1970s showed how to marry 119:is identical to that of first order logic ( 6056:. Vol. II. Amsterdam: North Holland. 5838: 5305: 5301: 4989:complete predicate, say EQUAL, such that: 2709:.(y x). This is typical. In general, the 6232: 6030:. Vol. I. Amsterdam: North Holland. 5874: 5691: 5682:does not belong to the deductive closure 5650: 5624: 5598: 5572: 5540: 5504: 5472: 5446: 5420: 5394: 5368: 5336: 5290: 5267: 5231: 4612:corresponding problems for lambda terms. 4123: 4111: 4108: 4084: 4078: 4053: 4044: 4039: 4036: 4015: 4010: 4004: 1695: 1673: 1660: 1650: 1626: 1601: 1582: 1572: 1562: 1556: 1540:{\displaystyle (E_{1}E_{2}E_{3}...E_{n})} 1528: 1509: 1499: 1489: 1480: 1341: 1311: 1278: 1242: 1209: 1151: 1115: 1043: 1021:represents the result of taking the term 989: 954: 941: 920: 891: 885: 860: 854: 829: 823: 790: 784: 759: 753: 728: 722: 690: 680: 671: 639: 633: 608: 602: 573: 558: 529: 523: 486: 471: 443: 437: 412: 406: 382: 351: 341: 332: 306: 291: 266: 6484:Lectures on the Curry–Howard Isomorphism 5886: 4603:Undecidability of combinatorial calculus 1784:The simplest example of a combinator is 1401: 966:{\displaystyle ((\lambda v.E_{1})E_{2})} 40:is a notation to eliminate the need for 5910: 5898: 5791: 5467:by modus ponens. On the other hand, if 4322:A distinction must be made between the 3338:Similarly, the original version of the 2059:) is yet another. We will use the word 1918:into each of them. Or put another way, 1610:{\displaystyle E_{1}E_{2}E_{3}...E_{n}} 6701:Combinatory logic reduction web server 5862: 5826: 1788:, the identity combinator, defined by 1025:and replacing all free occurrences of 64:and also as a basis for the design of 6296:(1996) . "Variables explained away". 6285: 6255:Foundations of Functional Programming 5814: 5321:{\displaystyle X\Vdash A\iff A\in X.} 5122:combinators correspond to the axioms 4750:has a normal form for every argument 4329:as described in this article and the 4303: 4251:'s original paper, what we now call 3106:Simplifications of the transformation 2070:A more interesting combinator is the 2039:of functions: that two functions are 1304:To evaluate the resulting expression 812:) is an abstraction, the term may be 56:, and has more recently been used in 7: 6406:Seldin, Jonathan P. (3 March 2008). 6266:(1960). "Variables explained away". 4428:term can be converted into an equal 4417:, which form a basis from which all 4369:has at least one free occurrence in 4352:calculus restricts abstractions to: 4302:, as demonstrated in Section 3.2 of 3443:It is not difficult to verify that: 878:in place of the formal parameter of 120: 6657:Stanford Encyclopedia of Philosophy 5492:{\displaystyle X\not \Vdash A\to B} 5083:. This enabled what Iverson called 5061:Compilation of functional languages 5032:If EQUAL would exist, then for all 4879:is supposed to be complete either: 3928:combinators, the transformation of 2067:for identical combinatorial terms. 158:. Curry and Feys (1958), and Curry 6457:Diagonalization and Self-Reference 3222:) (by η-reduction) 2717:to a combinatorial term of length 25: 6712:Combinators: 100-Year Celebration 5716:is not intuitionistically valid. 4871:NEGATION)) ≡ (NEGATION ABSURDUM). 4103:(traditional canonical notation: 4031:(traditional canonical notation: 4024:{\displaystyle =\mathbf {C} _{*}} 3604:, with the following reductions: 3115:The combinators generated by the 2677:The combinatory representation, ( 138:in late 1927. In the late 1930s, 34:, a topic in digital electronics. 6530:. In Calude, Cristian S. (ed.). 5535:, thus the deductive closure of 5524:{\displaystyle X,A\not \vdash B} 4243:'s doctoral thesis of 1930 (see 4127: 4124: 4112: 4085: 4057: 4054: 4040: 4011: 3385:)). With the η-reduction rule, 2252:It is related to the process of 1810:. Another simple combinator is 1259:" to indicate multiplication.) 66:functional programming languages 6408:"The Logic of Curry and Church" 6190:; Seldin, Jonathan P. (2008) . 5992:American Journal of Mathematics 3502:} is a basis, it follows that { 582:{\displaystyle \lambda v.E_{1}} 495:{\displaystyle \lambda v.E_{1}} 315:{\displaystyle \lambda v.E_{1}} 6671:1920–1931 Curry's block notes. 6613:Combinators: A Centennial View 6234:10.4467/20842589RM.18.002.8835 6114:Information Processing Letters 6052:; Seldin, Jonathan P. (1972). 5741:Combinatory categorial grammar 5705:{\displaystyle X\not \Vdash A} 5664:{\displaystyle Y\not \Vdash B} 5483: 5356:{\displaystyle X\Vdash A\to B} 5347: 5302: 4096:{\displaystyle =\mathbf {I} '} 2241:This process is also known as 1720:Reduction in combinatory logic 1701: 1679: 1666: 1643: 1640: 1628: 1534: 1482: 1433:One of the combinator symbols 1171: 1165: 1156: 1153: 1129: 1117: 1090: 1078: 1072: 1069: 1063: 1048: 1045: 1006: 994: 960: 947: 925: 922: 696: 673: 357: 334: 208:, primitive functions without 1: 6551:The Journal of Symbolic Logic 6221:Reports on Mathematical Logic 5726:Applicative computing systems 4379:As a consequence, combinator 2086:Completeness of the S-K basis 551:of the abstraction. The term 5736:Categorical abstract machine 5612:{\displaystyle Y\supseteq X} 5408:{\displaystyle Y\supseteq X} 4616:Undefinability by predicates 4212:The motivation here is that 2256:, which takes an expression 1462:The primitive functions are 702:{\displaystyle (E_{1}E_{2})} 626:— that is, it returns 363:{\displaystyle (E_{1}E_{2})} 6586:Wolfengagen, V. E. (2003). 6284:Reprinted as Chapter 23 of 6080:. BirkhĂ€user. pp. 5–6. 5851:Hindley & Meredith 1990 5560:{\displaystyle X\cup \{A\}} 5206:The calculus consisting of 4705:if there are two arguments 4645:represent the conventional 4394:calculus. The constants of 3157:, and applies the function 2339:) to a combinatorial term: 2115:may be defined as follows: 657:, with every occurrence of 72:, which were introduced by 6771: 6690:Drag 'n' Drop Combinators. 6258:. University of Cambridge. 6215:Lachowski, Ɓukasz (2018). 6198:Cambridge University Press 6136:; Meredith, David (1990). 5927:Barendregt, Hendrik Pieter 3510:programming language uses 3078:evidently fits the bill. 2772:is clearly equivalent to ( 2247:Summary of lambda calculus 661:replaced by the argument. 245: 242:Summary of lambda calculus 115:, the expressive power of 29: 6755:Logic in computer science 6675:Keenan, David C. (2001) " 6143:Journal of Symbolic Logic 6126:10.1016/j.ipl.2003.12.005 6074:The Combinatory Programme 5638:{\displaystyle Y\Vdash A} 5460:{\displaystyle Y\Vdash B} 5434:{\displaystyle Y\Vdash A} 5067:SASL programming language 2991:By extensional equality, 2760:is clearly equivalent to 2023:) itself is not equal to 1914:after first substituting 6381:Harvard University Press 6302:Harvard University Press 6294:Quine, Willard Van Orman 6264:Quine, Willard Van Orman 5262:, and we define a model 5097:Curry–Howard isomorphism 4955:, again a contradiction. 4220:are limited versions of 3514:as its sole combinator. 2783:does not appear free in 2055:are among these ways. ( 2027:. We say the terms are 2000:. Note that although (( 516:of the abstraction, and 150:and his students, or by 30:Not to be confused with 6717:Wolfram Physics Project 6461:Oxford University Press 5771:SKI combinator calculus 5756:Graph reduction machine 5686:of the empty set, thus 5275:{\displaystyle \Vdash } 4944:(NEGATION ABSURDUM) = ( 4918:(NEGATION ABSURDUM) = ( 4867:NEGATION) = (NEGATION ( 4383:is not present in the λ 3169:to combinatorial form. 2243:abstraction elimination 2162:does not occur free in 1926:inside the environment 1780:Examples of combinators 1177:{\displaystyle ((ab)c)} 1108:By convention, we take 746:is to be invoked, with 238:and combinatory logic. 117:predicate functor logic 105:predicate functor logic 48:. It was introduced by 6093:Functional Programming 5751:Fixed point combinator 5706: 5665: 5639: 5613: 5587: 5586:{\displaystyle Y\in W} 5561: 5525: 5493: 5461: 5435: 5409: 5383: 5382:{\displaystyle Y\in W} 5357: 5322: 5276: 5252: 5077:J programming language 4344:calculus. Unlike the λ 4236:only in the argument. 4135: 4097: 4065: 4025: 3506:} is a basis too. The 3400:) is transformed into 2072:fixed point combinator 1876:A third combinator is 1708: 1611: 1541: 1350: 1326: 1293: 1251: 1224: 1186:(i.e., application is 1178: 1136: 1097: 1013: 967: 901: 870: 839: 808:(sometimes called the 800: 769: 738: 703: 649: 618: 583: 539: 496: 453: 422: 391: 364: 316: 275: 217:functional programming 121:Quine 1960, 1966, 1976 6331:Mathematische Annalen 6298:Selected Logic Papers 6046:Curry, Haskell Brooks 6020:Curry, Haskell Brooks 5988:Curry, Haskell Brooks 5962:10.1145/114054.114065 5781:To Mock a Mockingbird 5746:Explicit substitution 5707: 5666: 5640: 5614: 5588: 5562: 5526: 5494: 5462: 5436: 5410: 5384: 5358: 5323: 5277: 5258:is an intuitionistic 5253: 4963:ABSURDUM) is neither 4136: 4098: 4066: 4026: 2833:₂). But substituting 1709: 1612: 1542: 1351: 1327: 1294: 1252: 1225: 1179: 1137: 1135:{\displaystyle (abc)} 1098: 1014: 968: 902: 900:{\displaystyle E_{1}} 871: 869:{\displaystyle E_{1}} 840: 838:{\displaystyle E_{2}} 801: 799:{\displaystyle E_{1}} 770: 768:{\displaystyle E_{2}} 739: 737:{\displaystyle E_{1}} 704: 650: 648:{\displaystyle E_{1}} 619: 617:{\displaystyle E_{1}} 584: 540: 538:{\displaystyle E_{1}} 497: 454: 452:{\displaystyle E_{2}} 423: 421:{\displaystyle E_{1}} 392: 365: 317: 276: 82:higher-order function 80:. A combinator is a 6523:Tromp, John (2008). 6383:. pp. 355–366. 6369:Van Heijenoort, Jean 6304:. pp. 227–235. 6250:Paulson, Lawrence C. 6071:Engeler, E. (1995). 5690: 5649: 5623: 5597: 5571: 5539: 5503: 5471: 5445: 5419: 5393: 5367: 5335: 5289: 5266: 5230: 5101:intuitionistic logic 4387:calculus nor in the 4107: 4077: 4035: 4003: 3736:, and much later by 2737:transformation": --> 2037:intensional equality 1625: 1555: 1479: 1371:Church–Turing thesis 1340: 1310: 1277: 1241: 1208: 1150: 1114: 1042: 988: 919: 884: 853: 822: 783: 752: 721: 670: 632: 601: 557: 522: 470: 436: 405: 381: 331: 290: 265: 191:computability theory 166:, which reviews the 136:Princeton University 98:quantified variables 86:function application 62:model of computation 6085:Field, Anthony J.; 4851:Define ABSURDUM ≡ ( 4649:of true and false, 4599:that we have seen. 3943:) looks like this: 2729:Explanation of the 2254:bracket abstraction 2029:extensionally equal 1619:, denotes the term 1386:Combinatory calculi 1325:{\displaystyle 3*3} 1292:{\displaystyle 3*3} 1271:The square of 3 is 1223:{\displaystyle x*x} 32:combinational logic 6634:Schönfinkel (1924) 6365:Schönfinkel, Moses 6357:Schönfinkel (1967) 6343:10.1007/bf01448013 6320:Schönfinkel, Moses 6097:. Addison-Wesley. 6087:Harrison, Peter G. 5956:. pp. 88–93. 5803:Schönfinkel (1967) 5702: 5661: 5635: 5609: 5583: 5557: 5521: 5489: 5457: 5431: 5405: 5379: 5353: 5318: 5272: 5248: 5073:Kenneth E. Iverson 4929:, a contradiction. 4811:Define NEGATION ≡ 4759: 4450:Reverse conversion 4158:) does reduce to ( 4131: 4093: 4061: 4021: 3594:Schönfinkel (1924) 1704: 1607: 1537: 1430:Primitive function 1346: 1322: 1289: 1247: 1220: 1174: 1132: 1093: 1009: 963: 897: 866: 835: 796: 765: 734: 699: 664:Terms of the form 645: 614: 579: 535: 492: 464:Terms of the form 461:are lambda-terms. 449: 418: 387: 360: 312: 271: 46:mathematical logic 6745:Combinatory logic 6709:(29 April 2020). 6684:Combinator Birds. 6682:Rathman, Chris, " 6661:Combinatory Logic 6644:978-1-57955-044-8 6627:978-1-57955-043-1 6453:Smullyan, Raymond 6426:Smullyan, Raymond 6188:Hindley, J. Roger 6134:Hindley, J. Roger 6054:Combinatory Logic 6050:Hindley, J. Roger 6028:Combinatory Logic 5933:. Vol. 103. 5765:Cylindric algebra 5731:B, C, K, W system 5533:deduction theorem 5282:in this frame by 5085:tacit programming 5079:, a successor to 4757: 4245:B, C, K, W System 1460: 1459: 1395:Combinatory terms 1379:Combinatory logic 1349:{\displaystyle *} 1250:{\displaystyle *} 1144:as shorthand for 1012:{\displaystyle E} 390:{\displaystyle v} 274:{\displaystyle v} 128:Moses Schönfinkel 113:first-order logic 68:. It is based on 60:as a theoretical 50:Moses Schönfinkel 38:Combinatory logic 18:Combinatory Logic 16:(Redirected from 6762: 6731: 6729: 6727: 6707:Wolfram, Stephen 6637: 6608:Wolfram, Stephen 6603: 6582: 6547:Turner, David A. 6542: 6540: 6529: 6519: 6517: 6516: 6510: 6504:. Archived from 6489: 6477: 6448: 6421: 6419: 6417: 6412: 6402: 6360: 6337:(3–4): 305–316. 6328: 6315: 6289: 6259: 6245: 6243: 6241: 6236: 6211: 6196:(2nd ed.). 6183: 6129: 6108: 6096: 6081: 6079: 6067: 6041: 6015: 5983: 5948: 5914: 5908: 5902: 5896: 5890: 5884: 5878: 5872: 5866: 5860: 5854: 5848: 5842: 5836: 5830: 5824: 5818: 5812: 5806: 5799:Schönfinkel 1924 5796: 5711: 5709: 5708: 5703: 5670: 5668: 5667: 5662: 5644: 5642: 5641: 5636: 5618: 5616: 5615: 5610: 5592: 5590: 5589: 5584: 5566: 5564: 5563: 5558: 5530: 5528: 5527: 5522: 5498: 5496: 5495: 5490: 5466: 5464: 5463: 5458: 5440: 5438: 5437: 5432: 5414: 5412: 5411: 5406: 5388: 5386: 5385: 5380: 5362: 5360: 5359: 5354: 5327: 5325: 5324: 5319: 5281: 5279: 5278: 5273: 5257: 5255: 5254: 5249: 4696: 4682: 4647:Church encodings 4644: 4638: 4171: 4140: 4138: 4137: 4132: 4130: 4119: 4115: 4102: 4100: 4099: 4094: 4092: 4088: 4070: 4068: 4067: 4062: 4060: 4049: 4048: 4043: 4030: 4028: 4027: 4022: 4020: 4019: 4014: 3996: 3984: 3975: 3963: 3954: 3949: 3903: 3872: 3846:is free in both 3841: 3814: 3802: 3782: 3767: 3752: 3580:Combinators B, C 3232: 3178: 2745: 2744: 2740: 2216: 2189: 2177: 2157: 2142: 2127: 2114: 2106: 1775: 1750: 1715: 1713: 1711: 1710: 1705: 1700: 1699: 1678: 1677: 1665: 1664: 1655: 1654: 1618: 1616: 1614: 1613: 1608: 1606: 1605: 1587: 1586: 1577: 1576: 1567: 1566: 1548: 1546: 1544: 1543: 1538: 1533: 1532: 1514: 1513: 1504: 1503: 1494: 1493: 1402: 1357: 1355: 1353: 1352: 1347: 1333: 1331: 1329: 1328: 1323: 1300: 1298: 1296: 1295: 1290: 1265:formal parameter 1258: 1256: 1254: 1253: 1248: 1231: 1229: 1227: 1226: 1221: 1188:left associative 1185: 1183: 1181: 1180: 1175: 1143: 1141: 1139: 1138: 1133: 1104: 1102: 1100: 1099: 1094: 1033:. Thus we write 1032: 1028: 1024: 1020: 1018: 1016: 1015: 1010: 974: 972: 970: 969: 964: 959: 958: 946: 945: 908: 906: 904: 903: 898: 896: 895: 877: 875: 873: 872: 867: 865: 864: 846: 844: 842: 841: 836: 834: 833: 807: 805: 803: 802: 797: 795: 794: 776: 774: 772: 771: 766: 764: 763: 745: 743: 741: 740: 735: 733: 732: 710: 708: 706: 705: 700: 695: 694: 685: 684: 656: 654: 652: 651: 646: 644: 643: 625: 623: 621: 620: 615: 613: 612: 590: 588: 586: 585: 580: 578: 577: 546: 544: 542: 541: 536: 534: 533: 514:formal parameter 503: 501: 499: 498: 493: 491: 490: 460: 458: 456: 455: 450: 448: 447: 429: 427: 425: 424: 419: 417: 416: 398: 396: 394: 393: 388: 371: 369: 367: 366: 361: 356: 355: 346: 345: 323: 321: 319: 318: 313: 311: 310: 282: 280: 278: 277: 272: 183:computer science 109:expressive power 58:computer science 21: 6770: 6769: 6765: 6764: 6763: 6761: 6760: 6759: 6750:Lambda calculus 6735: 6734: 6725: 6723: 6705: 6653: 6628: 6606: 6600: 6585: 6563:10.2307/2273733 6545: 6538: 6527: 6522: 6514: 6512: 6508: 6502: 6494:. p. 442. 6487: 6480: 6471: 6451: 6442: 6424: 6415: 6413: 6410: 6405: 6391: 6363: 6326: 6318: 6312: 6292: 6262: 6248: 6239: 6237: 6214: 6208: 6186: 6156:10.2307/2274956 6132: 6111: 6105: 6084: 6077: 6070: 6064: 6044: 6038: 6018: 6004:10.2307/2370619 5986: 5972: 5951: 5945: 5925: 5922: 5917: 5909: 5905: 5897: 5893: 5885: 5881: 5873: 5869: 5861: 5857: 5849: 5845: 5839:Barendregt 1984 5837: 5833: 5825: 5821: 5813: 5809: 5797: 5793: 5789: 5776:Supercombinator 5761:Lambda calculus 5722: 5688: 5687: 5647: 5646: 5621: 5620: 5595: 5594: 5569: 5568: 5537: 5536: 5501: 5500: 5469: 5468: 5443: 5442: 5417: 5416: 5391: 5390: 5365: 5364: 5333: 5332: 5287: 5286: 5264: 5263: 5228: 5227: 5093: 5063: 5058: 4982: 4735:. A combinator 4697:). A predicate 4684: 4674: 4640: 4634: 4618: 4605: 4454:The conversion 4452: 4445: 4438: 4434: 4427: 4423: 4400: 4393: 4386: 4351: 4348:calculus, the λ 4347: 4343: 4339: 4335: 4328: 4320: 4317: 4313: 4169: 4110: 4105: 4104: 4083: 4075: 4074: 4038: 4033: 4032: 4009: 4001: 4000: 3987: 3979: 3966: 3957: 3950: 3947: 3888: 3857: 3826: 3805: 3794: 3787:is not free in 3770: 3755: 3744: 3584:In addition to 3582: 3410: 3408:One-point basis 3230: 3176: 3138:is not free in 3113: 3108: 2845:₂) in place of 2821:₂) in place of 2746: 2742: 2738: 2736: 2735: 2322: 2221:occurs free in 2201: 2194:occurs free in 2180: 2169: 2145: 2130: 2119: 2110: 2102: 2088: 1782: 1772: 1766: 1759: 1744: 1738: 1728: 1722: 1691: 1669: 1656: 1646: 1623: 1622: 1620: 1597: 1578: 1568: 1558: 1553: 1552: 1550: 1524: 1505: 1495: 1485: 1477: 1476: 1474: 1397: 1388: 1367:Turing machines 1360:Church encoding 1338: 1337: 1335: 1308: 1307: 1305: 1275: 1274: 1272: 1239: 1238: 1236: 1206: 1205: 1203: 1148: 1147: 1145: 1112: 1111: 1109: 1040: 1039: 1037: 1030: 1026: 1022: 986: 985: 983: 982:The expression 950: 937: 917: 916: 914: 887: 882: 881: 879: 856: 851: 850: 848: 825: 820: 819: 817: 786: 781: 780: 778: 755: 750: 749: 747: 724: 719: 718: 716: 686: 676: 668: 667: 665: 635: 630: 629: 627: 604: 599: 598: 596: 569: 555: 554: 552: 525: 520: 519: 517: 508:. The variable 482: 468: 467: 465: 439: 434: 433: 431: 408: 403: 402: 400: 379: 378: 376: 347: 337: 329: 328: 326: 302: 288: 287: 285: 263: 262: 260: 250: 248:Lambda calculus 244: 202:lambda calculus 179: 144:lambda calculus 94: 84:that uses only 78:predicate logic 35: 28: 23: 22: 15: 12: 11: 5: 6768: 6766: 6758: 6757: 6752: 6747: 6737: 6736: 6733: 6732: 6703: 6698: 6693: 6687: 6680: 6673: 6668: 6652: 6651:External links 6649: 6648: 6647: 6626: 6604: 6598: 6583: 6557:(2): 267–270. 6543: 6541:on 2016-03-04. 6520: 6501:978-0444520777 6500: 6478: 6470:978-0198534501 6469: 6449: 6440: 6422: 6403: 6390:978-0674324497 6389: 6361: 6316: 6310: 6290: 6274:(3): 343–347. 6260: 6246: 6212: 6206: 6184: 6130: 6120:(6): 281–286. 6109: 6103: 6082: 6068: 6062: 6042: 6036: 6016: 5984: 5970: 5949: 5943: 5921: 5918: 5916: 5915: 5903: 5891: 5879: 5875:Lachowski 2018 5867: 5855: 5843: 5831: 5819: 5807: 5790: 5788: 5785: 5784: 5783: 5778: 5773: 5768: 5758: 5753: 5748: 5743: 5738: 5733: 5728: 5721: 5718: 5701: 5698: 5695: 5660: 5657: 5654: 5634: 5631: 5628: 5608: 5605: 5602: 5582: 5579: 5576: 5567:is an element 5556: 5553: 5550: 5547: 5544: 5520: 5517: 5514: 5511: 5508: 5488: 5485: 5482: 5479: 5476: 5456: 5453: 5450: 5430: 5427: 5424: 5404: 5401: 5398: 5378: 5375: 5372: 5352: 5349: 5346: 5343: 5340: 5329: 5328: 5317: 5314: 5311: 5308: 5304: 5300: 5297: 5294: 5271: 5247: 5244: 5241: 5238: 5235: 5204: 5203: 5177: 5176: 5142: 5105:Hilbert system 5092: 5089: 5062: 5059: 5057: 5054: 5030: 5029: 5010: 4957: 4956: 4930: 4903: 4902: 4892: 4873: 4872: 4857: 4856: 4849: 4808: 4807: 4793: 4756: 4617: 4614: 4604: 4601: 4593: 4592: 4579: 4547: 4518: 4490: 4473: 4451: 4448: 4443: 4436: 4432: 4425: 4421: 4398: 4391: 4384: 4377: 4376: 4375: 4374: 4349: 4345: 4341: 4337: 4333: 4326: 4319: 4315: 4311: 4308: 4291:respectively. 4210: 4209: 4199: 4186: 4143: 4142: 4129: 4126: 4122: 4118: 4114: 4091: 4087: 4082: 4072: 4059: 4056: 4052: 4047: 4042: 4018: 4013: 4008: 3998: 3985: 3977: 3964: 3955: 3918: 3917: 3886: 3855: 3824: 3803: 3792: 3768: 3753: 3730: 3729: 3691: 3661: 3660: 3633: 3581: 3578: 3574: 3573: 3557: 3539: 3492: 3491: 3466: 3441: 3440: 3409: 3406: 3336: 3335: 3328: 3314: 3297: 3279: 3253: 3224: 3223: 3204: 3185: 3182: 3144: 3143: 3112: 3109: 3107: 3104: 3076: 3075: 3027: 3026: 2989: 2988: 2987: 2986: 2985: 2984: 2983: 2982: 2981: 2980: 2955: 2879: 2878: 2734: 2733:transformation 2727: 2675: 2674: 2673: 2672: 2669: 2662: 2651: 2637: 2619: 2597: 2572: 2498: 2497: 2496: 2495: 2468: 2441: 2416: 2397: 2384: 2377: 2370: 2363: 2353: 2321: 2318: 2314: 2313: 2291: 2282: 2231: 2230: 2199: 2178: 2167: 2143: 2128: 2087: 2084: 1994: 1993: 1992: 1991: 1985: 1968: 1922:is applied to 1901: 1900: 1874: 1873: 1847:for all terms 1845: 1844: 1806:for all terms 1804: 1803: 1781: 1778: 1770: 1764: 1752: 1751: 1742: 1736: 1721: 1718: 1703: 1698: 1694: 1690: 1687: 1684: 1681: 1676: 1672: 1668: 1663: 1659: 1653: 1649: 1645: 1642: 1639: 1636: 1633: 1630: 1604: 1600: 1596: 1593: 1590: 1585: 1581: 1575: 1571: 1565: 1561: 1536: 1531: 1527: 1523: 1520: 1517: 1512: 1508: 1502: 1498: 1492: 1488: 1484: 1468:free variables 1458: 1457: 1454: 1451: 1447: 1446: 1431: 1428: 1424: 1423: 1420: 1417: 1413: 1412: 1409: 1406: 1396: 1393: 1387: 1384: 1345: 1321: 1318: 1315: 1302: 1301: 1288: 1285: 1282: 1246: 1233: 1232: 1219: 1216: 1213: 1198:The square of 1173: 1170: 1167: 1164: 1161: 1158: 1155: 1131: 1128: 1125: 1122: 1119: 1106: 1105: 1092: 1089: 1086: 1083: 1080: 1077: 1074: 1071: 1068: 1065: 1062: 1059: 1056: 1053: 1050: 1047: 1008: 1005: 1002: 999: 996: 993: 962: 957: 953: 949: 944: 940: 936: 933: 930: 927: 924: 894: 890: 863: 859: 832: 828: 793: 789: 762: 758: 731: 727: 698: 693: 689: 683: 679: 675: 642: 638: 611: 607: 576: 572: 568: 565: 562: 532: 528: 512:is called the 489: 485: 481: 478: 475: 446: 442: 415: 411: 386: 373: 372: 359: 354: 350: 344: 340: 336: 324: 309: 305: 301: 298: 295: 283: 270: 246:Main article: 243: 240: 219:languages and 210:free variables 178: 175: 93: 92:In mathematics 90: 26: 24: 14: 13: 10: 9: 6: 4: 3: 2: 6767: 6756: 6753: 6751: 6748: 6746: 6743: 6742: 6740: 6722: 6718: 6714: 6713: 6708: 6704: 6702: 6699: 6697: 6694: 6692:(Java Applet) 6691: 6688: 6685: 6681: 6678: 6674: 6672: 6669: 6666: 6665:Katalin BimbĂł 6662: 6658: 6655: 6654: 6650: 6645: 6641: 6636: 6635: 6629: 6623: 6619: 6618:Wolfram Media 6615: 6614: 6609: 6605: 6601: 6599:5-89158-101-9 6595: 6591: 6590: 6584: 6580: 6576: 6572: 6568: 6564: 6560: 6556: 6552: 6548: 6544: 6537: 6533: 6526: 6521: 6511:on 2005-10-16 6507: 6503: 6497: 6493: 6486: 6485: 6479: 6476: 6472: 6466: 6462: 6458: 6454: 6450: 6447: 6443: 6441:0-394-53491-3 6437: 6433: 6432: 6427: 6423: 6409: 6404: 6400: 6396: 6392: 6386: 6382: 6378: 6374: 6370: 6366: 6362: 6359: 6358: 6352: 6348: 6344: 6340: 6336: 6333:(in German). 6332: 6325: 6321: 6317: 6313: 6311:9780674798373 6307: 6303: 6299: 6295: 6291: 6288: 6287: 6281: 6277: 6273: 6269: 6265: 6261: 6257: 6256: 6251: 6247: 6235: 6230: 6227:(53): 19–42. 6226: 6222: 6218: 6213: 6209: 6207:9780521898850 6203: 6199: 6195: 6194: 6189: 6185: 6181: 6177: 6173: 6169: 6165: 6161: 6157: 6153: 6150:(1): 90–105. 6149: 6145: 6144: 6139: 6135: 6131: 6127: 6123: 6119: 6115: 6110: 6106: 6104:0-201-19249-7 6100: 6095: 6094: 6088: 6083: 6076: 6075: 6069: 6065: 6063:0-7204-2208-6 6059: 6055: 6051: 6047: 6043: 6039: 6037:0-7204-2208-6 6033: 6029: 6025: 6021: 6017: 6013: 6009: 6005: 6001: 5997: 5994:(in German). 5993: 5989: 5985: 5981: 5977: 5973: 5967: 5963: 5959: 5955: 5950: 5946: 5944:0-444-87508-5 5940: 5936: 5935:North Holland 5932: 5928: 5924: 5923: 5919: 5912: 5907: 5904: 5900: 5895: 5892: 5888: 5887:Goldberg 2004 5883: 5880: 5876: 5871: 5868: 5864: 5859: 5856: 5852: 5847: 5844: 5840: 5835: 5832: 5828: 5823: 5820: 5816: 5811: 5808: 5804: 5800: 5795: 5792: 5786: 5782: 5779: 5777: 5774: 5772: 5769: 5766: 5762: 5759: 5757: 5754: 5752: 5749: 5747: 5744: 5742: 5739: 5737: 5734: 5732: 5729: 5727: 5724: 5723: 5719: 5717: 5715: 5699: 5696: 5693: 5685: 5681: 5677: 5672: 5658: 5655: 5652: 5632: 5629: 5626: 5606: 5603: 5600: 5580: 5577: 5574: 5551: 5545: 5542: 5534: 5518: 5515: 5512: 5509: 5506: 5486: 5480: 5477: 5474: 5454: 5451: 5448: 5428: 5425: 5422: 5402: 5399: 5396: 5389:is such that 5376: 5373: 5370: 5350: 5344: 5341: 5338: 5315: 5312: 5309: 5306: 5298: 5295: 5292: 5285: 5284: 5283: 5269: 5261: 5242: 5239: 5236: 5225: 5221: 5217: 5213: 5209: 5201: 5197: 5193: 5189: 5185: 5182: 5181: 5180: 5174: 5170: 5166: 5162: 5158: 5154: 5150: 5146: 5143: 5140: 5136: 5132: 5128: 5125: 5124: 5123: 5121: 5117: 5112: 5110: 5106: 5102: 5098: 5090: 5088: 5086: 5082: 5078: 5074: 5070: 5068: 5060: 5055: 5053: 5051: 5045: 5043: 5039: 5035: 5027: 5023: 5019: 5015: 5011: 5008: 5004: 5000: 4996: 4992: 4991: 4990: 4988: 4981: 4980: 4979: 4974: 4970: 4966: 4962: 4954: 4950: 4947: 4943: 4939: 4935: 4931: 4928: 4924: 4921: 4917: 4913: 4909: 4905: 4904: 4901: 4897: 4893: 4890: 4886: 4882: 4881: 4880: 4878: 4870: 4866: 4862: 4861: 4860: 4854: 4850: 4847: 4844: 4840: 4837: 4833: 4829: 4825: 4821: 4818: 4814: 4810: 4809: 4805: 4801: 4798: 4794: 4791: 4787: 4784: 4780: 4779: 4778: 4776: 4772: 4768: 4764: 4755: 4753: 4749: 4746: 4742: 4738: 4734: 4730: 4727: 4723: 4719: 4716: 4712: 4708: 4704: 4700: 4694: 4691: 4687: 4681: 4677: 4672: 4668: 4664: 4660: 4656: 4652: 4648: 4643: 4637: 4632: 4628: 4624: 4615: 4613: 4610: 4602: 4600: 4598: 4590: 4587: 4583: 4580: 4577: 4574: 4570: 4567: 4563: 4559: 4555: 4551: 4548: 4545: 4542: 4538: 4534: 4530: 4526: 4522: 4519: 4516: 4513: 4510: 4506: 4502: 4498: 4494: 4491: 4489: 4485: 4481: 4477: 4474: 4472: 4468: 4464: 4461: 4460: 4459: 4457: 4449: 4447: 4442: 4431: 4420: 4416: 4412: 4408: 4404: 4397: 4390: 4382: 4372: 4368: 4364: 4360: 4357: 4356: 4355: 4354: 4353: 4332: 4325: 4309: 4307: 4305: 4301: 4297: 4292: 4290: 4286: 4282: 4278: 4274: 4270: 4266: 4262: 4258: 4254: 4250: 4246: 4242: 4241:Haskell Curry 4237: 4235: 4231: 4227: 4223: 4219: 4215: 4207: 4204: 4200: 4197: 4194: 4191: 4187: 4184: 4181: 4178: 4175: 4168: 4167: 4166: 4164: 4161: 4157: 4154: 4151: 4148: 4145:And indeed, ( 4120: 4116: 4089: 4080: 4073: 4050: 4045: 4016: 4006: 3999: 3997:(η-reduction) 3994: 3991: 3986: 3983: 3978: 3973: 3970: 3965: 3961: 3956: 3953: 3946: 3945: 3944: 3942: 3939: 3935: 3931: 3927: 3923: 3915: 3911: 3907: 3901: 3898: 3895: 3891: 3887: 3884: 3880: 3876: 3870: 3867: 3864: 3860: 3856: 3853: 3849: 3845: 3839: 3836: 3833: 3829: 3825: 3822: 3818: 3812: 3808: 3804: 3801: 3797: 3793: 3790: 3786: 3780: 3777: 3773: 3769: 3765: 3762: 3758: 3754: 3751: 3747: 3743: 3742: 3741: 3739: 3735: 3727: 3723: 3719: 3715: 3711: 3707: 3703: 3699: 3695: 3692: 3689: 3685: 3681: 3677: 3674: 3673: 3672: 3670: 3666: 3658: 3655: 3651: 3647: 3644: 3641: 3638: 3634: 3631: 3627: 3624: 3620: 3617: 3614: 3611: 3607: 3606: 3605: 3603: 3599: 3595: 3591: 3587: 3579: 3577: 3572: 3568: 3565: 3561: 3558: 3555: 3551: 3547: 3544: 3540: 3537: 3534: 3531: 3527: 3523: 3520: 3519: 3518: 3515: 3513: 3509: 3505: 3501: 3497: 3489: 3485: 3482: 3478: 3474: 3470: 3467: 3464: 3460: 3457: 3453: 3449: 3446: 3445: 3444: 3438: 3434: 3430: 3426: 3423: 3422: 3421: 3419: 3415: 3407: 3405: 3403: 3399: 3396: 3392: 3388: 3384: 3380: 3376: 3372: 3368: 3364: 3360: 3356: 3353: 3349: 3345: 3341: 3333: 3329: 3326: 3323: 3319: 3315: 3312: 3309: 3305: 3302: 3298: 3295: 3291: 3288: 3284: 3280: 3277: 3273: 3270: 3266: 3262: 3258: 3254: 3251: 3248: 3244: 3240: 3236: 3229: 3228: 3227: 3221: 3217: 3213: 3209: 3205: 3202: 3198: 3194: 3190: 3186: 3183: 3181: 3175: 3174: 3173: 3170: 3168: 3164: 3160: 3156: 3152: 3148: 3141: 3137: 3133: 3129: 3126: 3125: 3124: 3122: 3118: 3110: 3105: 3103: 3101: 3097: 3093: 3089: 3085: 3081: 3073: 3070: 3067: 3063: 3062: 3061: 3059: 3055: 3051: 3047: 3044: 3040: 3036: 3032: 3024: 3020: 3016: 3012: 3009: 3005: 3001: 2997: 2994: 2993: 2992: 2978: 2974: 2970: 2967: 2963: 2960: 2956: 2953: 2949: 2945: 2941: 2937: 2934: 2930: 2929: 2928: 2927: 2926: 2925: 2924: 2923: 2921: 2917: 2913: 2909: 2905: 2901: 2897: 2893: 2889: 2885: 2881: 2880: 2876: 2872: 2868: 2864: 2860: 2859: 2858: 2856: 2852: 2848: 2844: 2840: 2836: 2832: 2828: 2824: 2820: 2816: 2812: 2808: 2804: 2800: 2796: 2792: 2788: 2786: 2782: 2778: 2775: 2771: 2767: 2763: 2759: 2755: 2751: 2741: 2732: 2728: 2726: 2724: 2720: 2716: 2712: 2708: 2704: 2700: 2696: 2692: 2688: 2684: 2680: 2670: 2667: 2663: 2660: 2656: 2652: 2649: 2645: 2642: 2638: 2635: 2631: 2628: 2624: 2620: 2617: 2613: 2610: 2606: 2602: 2598: 2595: 2591: 2588: 2584: 2580: 2577: 2573: 2570: 2566: 2563: 2559: 2555: 2552: 2548: 2544: 2543: 2541: 2537: 2534: 2530: 2526: 2523: 2519: 2515: 2511: 2510: 2509: 2507: 2503: 2493: 2489: 2485: 2481: 2477: 2473: 2469: 2466: 2462: 2458: 2454: 2450: 2446: 2442: 2439: 2436: 2433: 2429: 2425: 2421: 2417: 2414: 2410: 2406: 2402: 2398: 2395: 2392: 2389: 2385: 2382: 2378: 2375: 2371: 2368: 2364: 2361: 2358: 2354: 2351: 2347: 2346: 2345: 2342: 2341: 2340: 2338: 2335: 2331: 2327: 2319: 2317: 2311: 2307: 2303: 2299: 2296: 2292: 2290: 2286: 2283: 2281: 2278: 2274: 2271: 2270: 2269: 2267: 2263: 2259: 2255: 2250: 2248: 2244: 2239: 2236: 2228: 2224: 2220: 2214: 2211: 2208: 2204: 2200: 2197: 2193: 2187: 2183: 2179: 2176: 2172: 2168: 2165: 2161: 2155: 2152: 2148: 2144: 2140: 2137: 2133: 2129: 2126: 2122: 2118: 2117: 2116: 2113: 2108: 2105: 2100: 2096: 2092: 2085: 2083: 2081: 2077: 2073: 2068: 2066: 2062: 2058: 2054: 2050: 2046: 2042: 2038: 2034: 2030: 2026: 2022: 2018: 2014: 2011: 2007: 2003: 1999: 1996:for any term 1990: 1986: 1983: 1980: 1976: 1973: 1969: 1966: 1963: 1959: 1958: 1956: 1952: 1948: 1947: 1946: 1944: 1940: 1936: 1931: 1929: 1925: 1921: 1917: 1913: 1909: 1905: 1898: 1894: 1890: 1887: 1883: 1882: 1881: 1879: 1872: 1868: 1865: 1862: 1858: 1857: 1856: 1854: 1850: 1843: 1839: 1835: 1832: 1828: 1827: 1826: 1824: 1820: 1817: 1813: 1809: 1802: 1798: 1795: 1791: 1790: 1789: 1787: 1779: 1777: 1773: 1763: 1757: 1749: 1745: 1735: 1732: 1727: 1726: 1725: 1719: 1717: 1696: 1692: 1688: 1685: 1682: 1674: 1670: 1661: 1657: 1651: 1647: 1637: 1634: 1631: 1602: 1598: 1594: 1591: 1588: 1583: 1579: 1573: 1569: 1563: 1559: 1529: 1525: 1521: 1518: 1515: 1510: 1506: 1500: 1496: 1490: 1486: 1471: 1469: 1465: 1455: 1452: 1449: 1448: 1444: 1440: 1436: 1432: 1429: 1426: 1425: 1421: 1418: 1415: 1414: 1410: 1407: 1404: 1403: 1400: 1394: 1392: 1385: 1383: 1380: 1374: 1372: 1368: 1363: 1361: 1343: 1319: 1316: 1313: 1286: 1283: 1280: 1270: 1269: 1268: 1266: 1262: 1244: 1217: 1214: 1211: 1201: 1197: 1196: 1195: 1191: 1189: 1168: 1162: 1159: 1126: 1123: 1120: 1087: 1084: 1081: 1075: 1066: 1060: 1057: 1054: 1051: 1036: 1035: 1034: 1003: 1000: 997: 991: 980: 978: 955: 951: 942: 938: 934: 931: 928: 912: 892: 888: 861: 857: 830: 826: 815: 811: 791: 787: 760: 756: 729: 725: 714: 691: 687: 681: 677: 662: 660: 640: 636: 609: 605: 594: 574: 570: 566: 563: 560: 550: 530: 526: 515: 511: 507: 487: 483: 479: 476: 473: 462: 444: 440: 413: 409: 384: 352: 348: 342: 338: 325: 307: 303: 299: 296: 293: 284: 268: 259: 258: 257: 255: 249: 241: 239: 237: 233: 228: 226: 222: 218: 215: 211: 207: 203: 198: 196: 192: 188: 184: 176: 174: 172: 169: 165: 161: 157: 153: 149: 148:Haskell Curry 145: 141: 140:Alonzo Church 137: 133: 132:Haskell Curry 129: 124: 122: 118: 114: 110: 106: 103: 99: 91: 89: 87: 83: 79: 75: 71: 67: 63: 59: 55: 54:Haskell Curry 51: 47: 44:variables in 43: 39: 33: 19: 6726:26 September 6724:. Retrieved 6711: 6631: 6612: 6588: 6554: 6550: 6536:the original 6531: 6513:. Retrieved 6506:the original 6483: 6474: 6456: 6445: 6429: 6416:17 September 6414:. Retrieved 6376: 6372: 6354: 6334: 6330: 6297: 6286:Quine (1996) 6283: 6271: 6267: 6254: 6238:. Retrieved 6224: 6220: 6192: 6147: 6141: 6117: 6113: 6092: 6073: 6053: 6027: 6024:Feys, Robert 5995: 5991: 5953: 5930: 5911:Cherlin 1991 5906: 5899:Engeler 1995 5894: 5882: 5870: 5858: 5846: 5834: 5822: 5810: 5794: 5713: 5683: 5679: 5675: 5673: 5330: 5260:Kripke frame 5219: 5215: 5211: 5207: 5205: 5199: 5195: 5191: 5187: 5183: 5178: 5172: 5168: 5164: 5160: 5156: 5152: 5148: 5144: 5138: 5134: 5130: 5126: 5119: 5115: 5113: 5109:proof theory 5094: 5071: 5064: 5056:Applications 5049: 5046: 5041: 5037: 5033: 5031: 5025: 5021: 5017: 5013: 5006: 5002: 4998: 4994: 4986: 4983: 4976: 4972: 4968: 4964: 4960: 4958: 4952: 4948: 4945: 4941: 4940:ABSURDUM) = 4937: 4933: 4926: 4922: 4919: 4915: 4914:ABSURDUM) = 4911: 4907: 4899: 4898:ABSURDUM) = 4895: 4888: 4887:ABSURDUM) = 4884: 4876: 4874: 4868: 4864: 4863:ABSURDUM ≡ ( 4858: 4852: 4845: 4842: 4838: 4835: 4831: 4827: 4823: 4819: 4816: 4812: 4803: 4799: 4796: 4789: 4785: 4782: 4774: 4770: 4766: 4762: 4760: 4751: 4747: 4744: 4740: 4736: 4732: 4728: 4725: 4721: 4717: 4714: 4710: 4706: 4702: 4698: 4692: 4689: 4685: 4679: 4675: 4670: 4666: 4662: 4658: 4654: 4650: 4641: 4635: 4630: 4626: 4622: 4619: 4606: 4596: 4594: 4588: 4585: 4581: 4575: 4572: 4568: 4565: 4561: 4557: 4553: 4549: 4543: 4540: 4536: 4532: 4528: 4524: 4520: 4514: 4511: 4508: 4504: 4500: 4496: 4492: 4487: 4483: 4479: 4475: 4470: 4466: 4462: 4455: 4453: 4440: 4429: 4418: 4414: 4410: 4406: 4402: 4395: 4388: 4380: 4378: 4370: 4366: 4362: 4358: 4330: 4323: 4321: 4304:Tromp (2008) 4299: 4295: 4293: 4288: 4284: 4280: 4276: 4272: 4271:were called 4268: 4264: 4260: 4256: 4252: 4238: 4233: 4229: 4225: 4221: 4217: 4213: 4211: 4205: 4202: 4195: 4192: 4189: 4182: 4179: 4176: 4173: 4170:   4162: 4159: 4155: 4152: 4149: 4146: 4144: 3992: 3989: 3981: 3971: 3968: 3959: 3951: 3948:   3940: 3937: 3933: 3929: 3925: 3921: 3919: 3913: 3909: 3905: 3899: 3896: 3893: 3889: 3882: 3878: 3874: 3868: 3865: 3862: 3858: 3851: 3847: 3843: 3837: 3834: 3831: 3827: 3820: 3816: 3810: 3806: 3799: 3795: 3788: 3784: 3778: 3775: 3771: 3763: 3760: 3756: 3749: 3745: 3738:David Turner 3731: 3725: 3721: 3717: 3713: 3709: 3705: 3701: 3697: 3693: 3687: 3683: 3679: 3675: 3668: 3664: 3662: 3656: 3653: 3649: 3645: 3642: 3639: 3636: 3629: 3625: 3622: 3618: 3615: 3612: 3609: 3601: 3597: 3589: 3585: 3583: 3575: 3570: 3566: 3563: 3559: 3553: 3549: 3545: 3542: 3535: 3532: 3529: 3525: 3521: 3516: 3511: 3503: 3499: 3495: 3493: 3487: 3483: 3480: 3476: 3472: 3468: 3462: 3458: 3455: 3451: 3447: 3442: 3436: 3432: 3428: 3424: 3417: 3413: 3411: 3401: 3397: 3394: 3390: 3386: 3382: 3378: 3374: 3370: 3366: 3362: 3358: 3354: 3351: 3347: 3343: 3339: 3337: 3331: 3324: 3321: 3317: 3310: 3307: 3303: 3300: 3293: 3289: 3286: 3282: 3275: 3271: 3268: 3264: 3260: 3256: 3249: 3246: 3242: 3238: 3234: 3231:   3225: 3219: 3215: 3211: 3207: 3200: 3196: 3192: 3188: 3179: 3177:   3171: 3166: 3162: 3158: 3154: 3150: 3146: 3145: 3139: 3135: 3131: 3127: 3120: 3116: 3114: 3099: 3095: 3091: 3087: 3083: 3079: 3077: 3071: 3068: 3065: 3057: 3053: 3049: 3045: 3042: 3038: 3034: 3030: 3028: 3022: 3018: 3014: 3010: 3007: 3003: 2999: 2995: 2990: 2976: 2972: 2968: 2965: 2961: 2958: 2951: 2947: 2943: 2939: 2935: 2932: 2919: 2915: 2911: 2907: 2903: 2899: 2895: 2891: 2887: 2883: 2874: 2870: 2866: 2862: 2854: 2850: 2846: 2842: 2838: 2834: 2830: 2826: 2825:, yielding ( 2822: 2818: 2814: 2810: 2806: 2802: 2798: 2797: 2793: 2789: 2784: 2780: 2776: 2773: 2769: 2765: 2761: 2757: 2753: 2749: 2747: 2730: 2722: 2714: 2710: 2706: 2702: 2698: 2694: 2690: 2686: 2682: 2678: 2676: 2665: 2658: 2654: 2647: 2643: 2640: 2633: 2629: 2626: 2622: 2615: 2611: 2608: 2604: 2600: 2593: 2589: 2586: 2582: 2578: 2575: 2568: 2564: 2561: 2557: 2553: 2550: 2546: 2539: 2535: 2532: 2528: 2524: 2521: 2517: 2513: 2505: 2501: 2499: 2491: 2487: 2483: 2479: 2475: 2471: 2464: 2460: 2456: 2452: 2448: 2444: 2437: 2434: 2431: 2427: 2423: 2419: 2412: 2408: 2404: 2400: 2393: 2390: 2387: 2380: 2373: 2366: 2359: 2356: 2349: 2343: 2336: 2333: 2329: 2325: 2323: 2315: 2309: 2305: 2301: 2297: 2294: 2288: 2284: 2279: 2276: 2272: 2265: 2261: 2257: 2253: 2251: 2242: 2240: 2234: 2232: 2226: 2222: 2218: 2212: 2209: 2206: 2202: 2195: 2191: 2185: 2181: 2174: 2170: 2163: 2159: 2153: 2150: 2146: 2138: 2135: 2131: 2124: 2120: 2111: 2109: 2103: 2098: 2094: 2090: 2089: 2075: 2069: 2064: 2060: 2056: 2052: 2048: 2040: 2036: 2032: 2024: 2020: 2016: 2012: 2009: 2005: 2001: 1997: 1995: 1988: 1981: 1978: 1974: 1971: 1964: 1961: 1954: 1950: 1942: 1938: 1934: 1932: 1927: 1923: 1919: 1915: 1911: 1907: 1903: 1902: 1896: 1892: 1888: 1885: 1877: 1875: 1870: 1866: 1863: 1860: 1852: 1848: 1846: 1841: 1837: 1833: 1830: 1825:, so we say 1822: 1818: 1815: 1811: 1807: 1805: 1800: 1796: 1793: 1785: 1783: 1768: 1761: 1755: 1753: 1747: 1740: 1733: 1730: 1723: 1472: 1463: 1461: 1442: 1438: 1434: 1411:Description 1398: 1389: 1378: 1375: 1364: 1303: 1263:here is the 1260: 1234: 1199: 1192: 1107: 981: 910: 813: 809: 713:applications 712: 663: 658: 592: 548: 509: 506:abstractions 505: 463: 374: 254:lambda-terms 253: 251: 236:model theory 229: 205: 199: 195:proof theory 180: 177:In computing 159: 125: 107:. While the 95: 69: 37: 36: 6240:9 September 5863:Turner 1979 5827:Seldin 2008 4609:normal form 4439:terms into 4249:Schönfinkel 3976:(by rule 7) 3908:is free in 3877:is free in 3819:is free in 3121:η-reduction 3111:η-reduction 1464:combinators 1453:Application 1029:in it with 977:normal form 711:are called 504:are called 206:combinators 187:computation 152:Robert Feys 74:Schönfinkel 70:combinators 6739:Categories 6515:2017-04-22 5971:0897914414 5920:Literature 5815:Curry 1930 5787:References 5593:such that 4777:such that 4765:. Because 4713:such that 4703:nontrivial 4224:. Whereas 3006:₂) = ( 2376:))] (by 3) 2300:) := 2233:Note that 2061:equivalent 2015:) for any 1549:, or even 911:equivalent 232:Dana Scott 214:non-strict 189:, used in 171:Dana Scott 164:Barendregt 42:quantified 6434:. Knopf. 6399:503886453 6367:(1967) . 6351:118507515 5630:⊩ 5604:⊇ 5578:∈ 5546:∪ 5484:→ 5452:⊩ 5426:⊩ 5400:⊇ 5374:∈ 5348:→ 5342:⊩ 5310:∈ 5303:⟺ 5296:⊩ 5270:⊩ 5246:⟩ 5243:⊆ 5234:⟨ 5224:inclusion 4855:NEGATION) 4623:predicate 4340:and the λ 4314:versus CL 4046:∗ 4017:∗ 3420:} where: 2494:)) (by 4) 2467:)) (by 3) 2440:)) (by 6) 2369:)] (by 4) 2362:)] (by 6) 2287: := 2275: := 2080:recursion 1344:∗ 1317:∗ 1284:∗ 1245:∗ 1215:∗ 1073:⇒ 1052:λ 929:λ 810:applicand 561:λ 474:λ 294:λ 6638:(eBook: 6610:(2021). 6579:35835482 6492:Elsevier 6455:(1994). 6428:(1985). 6322:(1924). 6252:(1995). 6089:(1998). 6026:(1958). 5980:25802202 5929:(1984). 5720:See also 5697:⊮ 5656:⊮ 5516:⊬ 5478:⊮ 4932:Case 2: 4906:Case 1: 4875:Because 4741:complete 4318:calculus 4117:′ 4090:′ 3912:but not 3881:but not 3357:) into ( 3060:₂), and 2415:) (by 3) 2396:) (by 6) 2352:] (by 5) 2249:above). 1906:applies 1419:Variable 1235:(Using " 225:Unlambda 221:hardware 6721:YouTube 6571:2273733 6371:(ed.). 6180:6930576 6172:1043546 6164:2274956 6012:2370619 5531:by the 5499:, then 5441:, then 5226:. Then 5186:: from 5159:)) → (( 5040:(EQUAL 5012:(EQUAL 4993:(EQUAL 4959:Hence ( 4822:) then 4633:(where 3494:Since { 2671:= (y x) 2542:) x y) 1714:⁠ 1621:⁠ 1617:⁠ 1551:⁠ 1547:⁠ 1475:⁠ 1356:⁠ 1336:⁠ 1332:⁠ 1306:⁠ 1299:⁠ 1273:⁠ 1257:⁠ 1237:⁠ 1230:⁠ 1204:⁠ 1184:⁠ 1146:⁠ 1142:⁠ 1110:⁠ 1103:⁠ 1038:⁠ 1019:⁠ 984:⁠ 973:⁠ 915:⁠ 907:⁠ 880:⁠ 876:⁠ 849:⁠ 845:⁠ 818:⁠ 814:reduced 806:⁠ 779:⁠ 775:⁠ 748:⁠ 744:⁠ 717:⁠ 709:⁠ 666:⁠ 655:⁠ 628:⁠ 624:⁠ 597:⁠ 589:⁠ 553:⁠ 547:is the 545:⁠ 518:⁠ 502:⁠ 466:⁠ 459:⁠ 432:⁠ 428:⁠ 401:⁠ 397:⁠ 377:⁠ 370:⁠ 327:⁠ 322:⁠ 286:⁠ 281:⁠ 261:⁠ 156:Belgium 102:Quine's 6642:  6624:  6596:  6577:  6569:  6498:  6467:  6438:  6397:  6387:  6349:  6308:  6280:985250 6278:  6204:  6178:  6170:  6162:  6101:  6060:  6034:  6010:  5978:  5968:  5941:  5712:, and 5645:, and 5363:, and 5214:, and 5198:infer 4978:Q.E.D. 4815:.(if ( 4365:where 4287:, and 4247:). In 3920:Using 3621:) = (( 3538:) with 3486:))) = 3123:rule: 3082:₁ and 2898:) = (( 2869:₂) = ( 2857:₂, so 2853:₁ and 2837:into ( 2764:, and 2664:= (y ( 2661:x) y)) 2653:= (y ( 2650:x) y)) 2639:= (y ( 2621:= (y ( 2556:) x ( 2482:)) ( 2455:)) ( 2430:)) ( 2383:(by 1) 2051:) and 1933:Given 1754:where 1405:Syntax 375:where 168:models 160:et al. 6663:" by 6575:S2CID 6567:JSTOR 6539:(PDF) 6528:(PDF) 6509:(PDF) 6488:(PDF) 6411:(PDF) 6375:[ 6347:S2CID 6327:(PDF) 6276:JSTOR 6176:S2CID 6160:JSTOR 6078:(PDF) 6008:JSTOR 5976:S2CID 5167:) → ( 5091:Logic 4826:else 4758:Proof 4401:are: 3734:Curry 3648:) = ( 3461:)) = 3245:)) 3218:)) 3199:)) 3184:= ... 2779:) if 2636:x y)) 2618:x y)) 2596:x) y) 2571:x) y) 2411:)) 2225:₁ or 2065:equal 2057:S K S 2049:S K K 2045:up to 2041:equal 2033:equal 2021:S K K 2008:) = ( 2002:S K K 1962:S K K 1951:S K K 1891:) = ( 1889:x y z 1450:(M N) 6728:2023 6640:ISBN 6622:ISBN 6594:ISBN 6496:ISBN 6465:ISBN 6436:ISBN 6418:2023 6395:OCLC 6385:ISBN 6306:ISBN 6242:2018 6225:2018 6202:ISBN 6099:ISBN 6058:ISBN 6032:ISBN 5966:ISBN 5939:ISBN 5763:and 5674:Let 5415:and 5190:and 5118:and 5114:The 5095:The 5016:) = 4997:) = 4967:nor 4951:) = 4925:) = 4830:) ≡ 4802:) = 4788:) = 4773:and 4724:and 4709:and 4683:and 4661:and 4639:and 4413:and 4298:and 4267:and 4216:and 3924:and 3904:(if 3873:(if 3850:and 3842:(if 3815:(if 3783:(if 3667:and 3600:and 3588:and 3569:) = 3528:.(x 3508:Iota 3431:.((x 3381:)) ( 3134:(if 2957:= (( 2748:The 2739:edit 2689:)) ( 2632:) 2614:) 2592:) 2567:) 2527:)) ( 2504:and 2217:(if 2190:(if 2158:(if 2093:and 1970:= ( 1960:= ( 1937:and 1869:) = 1851:and 1840:) = 1799:) = 1767:... 1746:) = 1739:... 1408:Name 549:body 430:and 193:and 52:and 6719:on 6659:: " 6559:doi 6339:doi 6272:104 6229:doi 6152:doi 6122:doi 6000:doi 5958:doi 5175:)), 5151:→ ( 5147:: ( 5133:→ ( 5107:in 5081:APL 5042:x A 5038:λx. 5020:if 5014:A B 5009:and 5001:if 4995:A B 4936:= ( 4910:= ( 4834:.(( 4792:and 4743:if 4739:is 4701:is 4688:= ( 4629:or 4584:= ( 4201:= ( 4188:= ( 4165:): 3988:= ( 3892:⇒ ( 3861:⇒ ( 3830:⇒ ( 3774:⇒ ( 3759:⇒ ( 3726:K K 3724:) ( 3720:)) 3714:K S 3696:= ( 3684:K S 3678:= ( 3556:and 3465:and 3414:any 3383:K I 3375:K K 3369:) ( 3367:K S 3332:y x 3330:= ( 3325:x y 3316:= ( 3311:x y 3299:= ( 3283:S I 3281:= ( 3261:S I 3255:= ( 3250:x y 3243:S I 3216:S I 3206:= ( 3197:S I 3187:= ( 2975:₂) 2931:= ( 2922:)) 2910:) ( 2894:₂) 2725:). 2695:K K 2687:S I 2668:x)) 2646:x ( 2603:y ( 2599:= ( 2574:= ( 2545:= ( 2488:K K 2480:S I 2470:= ( 2461:K K 2453:S I 2443:= ( 2428:S I 2418:= ( 2409:S I 2399:= ( 2386:= ( 2262:E x 2205:⇒ ( 2149:⇒ ( 2134:⇒ ( 2099:any 2074:or 2019:, ( 1987:= 1910:to 1897:y z 1893:x z 1202:is 1190:). 181:In 154:in 123:). 6741:: 6715:. 6630:. 6620:. 6616:. 6573:. 6565:. 6555:44 6553:. 6473:. 6463:. 6444:. 6393:. 6353:. 6345:. 6335:92 6329:. 6282:. 6270:. 6223:. 6219:. 6200:. 6174:. 6168:MR 6166:. 6158:. 6148:55 6146:. 6140:. 6118:89 6116:. 6048:; 6022:; 6006:. 5996:52 5974:. 5964:. 5937:. 5671:. 5619:, 5216:MP 5212:AS 5210:, 5208:AK 5194:→ 5184:MP 5171:→ 5163:→ 5155:→ 5145:AS 5141:), 5137:→ 5129:: 5127:AK 5111:. 5069:. 5036:, 5024:≠ 5005:= 4987:no 4891:or 4841:) 4832:λx 4813:λx 4731:= 4720:= 4678:= 4667:λy 4663:λx 4655:λy 4651:λx 4607:A 4578:)) 4564:.( 4562:λz 4558:λy 4554:λx 4552:= 4546:)) 4535:.( 4533:λz 4529:λy 4525:λx 4523:= 4507:.( 4505:λz 4501:λy 4497:λx 4495:= 4484:λy 4480:λx 4478:= 4467:λx 4465:= 4441:CL 4430:CL 4419:CL 4409:, 4405:, 4396:CL 4389:CL 4359:λx 4331:CL 4324:CL 4310:CL 4306:. 4283:, 4279:, 4275:, 4263:, 4259:, 4255:, 3980:= 3974:)] 3967:= 3958:= 3936:.( 3934:λy 3930:λx 3914:E₁ 3910:E₂ 3883:E₂ 3879:E₁ 3852:E₂ 3848:E₁ 3809:⇒ 3798:⇒ 3748:⇒ 3728:)) 3716:) 3686:) 3671:: 3659:)) 3628:) 3592:, 3567:X' 3564:X' 3560:X' 3552:= 3550:X' 3548:) 3546:X' 3543:X' 3526:λx 3524:≡ 3522:X' 3498:, 3429:λx 3427:≡ 3404:. 3393:.( 3391:λx 3387:λf 3377:) 3350:.( 3348:λx 3344:λf 3327:)) 3313:)) 3292:) 3274:) 3263:) 3149:.( 3147:λx 3130:= 3102:. 3096:λx 3090:₁ 3054:λx 3052:₁ 3046:λx 3037:₁ 3033:.( 3031:λx 3025:₂) 3019:λx 3017:₁ 3011:λx 3002:₁ 2998:.( 2996:λx 2969:λx 2966:E₁ 2962:λx 2950:₂ 2944:λx 2942:₁ 2936:λx 2918:₂ 2912:λx 2906:₁ 2900:λx 2890:₁ 2886:.( 2884:λx 2877:₂) 2873:₁ 2865:₁ 2841:₁ 2829:₁ 2817:₁ 2805:₁ 2801:.( 2799:λx 2787:. 2766:λx 2754:λx 2707:λy 2703:λx 2697:) 2538:) 2490:) 2463:) 2379:= 2372:= 2365:= 2355:= 2348:= 2332:.( 2330:λy 2326:λx 2310:E₂ 2308:)( 2306:E₁ 2298:E₂ 2295:E₁ 2264:= 2229:₂) 2184:⇒ 2173:⇒ 2123:⇒ 2082:. 2004:) 1984:)) 1957:) 1953:) 1949:(( 1941:, 1930:. 1899:)) 1836:) 1829:(( 1470:. 1445:. 1441:, 1437:, 1362:. 1085::= 1001::= 979:. 816:: 6730:. 6679:" 6667:. 6646:) 6602:. 6581:. 6561:: 6518:. 6420:. 6401:. 6341:: 6314:. 6244:. 6231:: 6210:. 6182:. 6154:: 6128:. 6124:: 6107:. 6066:. 6040:. 6014:. 6002:: 5982:. 5960:: 5947:. 5913:. 5901:. 5889:. 5877:. 5865:. 5853:. 5841:. 5829:. 5817:. 5805:. 5714:A 5700:A 5694:X 5684:X 5680:A 5676:A 5659:B 5653:Y 5633:A 5627:Y 5607:X 5601:Y 5581:W 5575:Y 5555:} 5552:A 5549:{ 5543:X 5519:B 5513:A 5510:, 5507:X 5487:B 5481:A 5475:X 5455:B 5449:Y 5429:A 5423:Y 5403:X 5397:Y 5377:W 5371:Y 5351:B 5345:A 5339:X 5316:. 5313:X 5307:A 5299:A 5293:X 5240:, 5237:W 5220:W 5202:. 5200:B 5196:B 5192:A 5188:A 5173:C 5169:A 5165:B 5161:A 5157:C 5153:B 5149:A 5139:A 5135:B 5131:A 5120:S 5116:K 5050:K 5034:A 5028:. 5026:B 5022:A 5018:F 5007:B 5003:A 4999:T 4973:N 4969:F 4965:T 4961:N 4953:F 4949:B 4946:N 4942:N 4938:N 4934:T 4927:T 4923:A 4920:N 4916:N 4912:N 4908:F 4900:T 4896:N 4894:( 4889:F 4885:N 4883:( 4877:N 4869:Y 4865:Y 4853:Y 4848:) 4846:A 4843:B 4839:x 4836:N 4828:A 4824:B 4820:x 4817:N 4806:. 4804:F 4800:B 4797:N 4795:( 4790:T 4786:A 4783:N 4781:( 4775:B 4771:A 4767:N 4763:N 4752:M 4748:M 4745:N 4737:N 4733:F 4729:B 4726:N 4722:T 4718:A 4715:N 4711:B 4707:A 4699:N 4695:) 4693:I 4690:K 4686:F 4680:K 4676:T 4671:y 4669:. 4665:. 4659:x 4657:. 4653:. 4642:F 4636:T 4631:F 4627:T 4597:T 4591:) 4589:L 4586:L 4582:L 4576:z 4573:y 4571:( 4569:z 4566:x 4560:. 4556:. 4550:L 4544:z 4541:y 4539:( 4537:x 4531:. 4527:. 4521:L 4517:) 4515:y 4512:z 4509:x 4503:. 4499:. 4493:L 4488:x 4486:. 4482:. 4476:L 4471:x 4469:. 4463:L 4456:L 4444:K 4437:K 4433:I 4426:I 4422:I 4415:S 4411:C 4407:B 4403:I 4399:I 4392:I 4385:I 4381:K 4373:. 4371:E 4367:x 4363:E 4361:. 4350:I 4346:K 4342:I 4338:K 4334:I 4327:K 4316:I 4312:K 4300:C 4296:B 4289:T 4285:Z 4281:I 4277:C 4273:S 4269:C 4265:B 4261:I 4257:K 4253:S 4234:B 4230:C 4226:S 4222:S 4218:C 4214:B 4208:) 4206:x 4203:y 4198:) 4196:x 4193:y 4190:I 4185:) 4183:y 4180:x 4177:I 4174:C 4172:( 4163:x 4160:y 4156:y 4153:x 4150:I 4147:C 4141:) 4128:X 4125:C 4121:= 4113:X 4086:I 4081:= 4071:) 4058:I 4055:X 4051:= 4041:X 4012:C 4007:= 3995:) 3993:I 3990:C 3982:T 3972:x 3969:T 3962:] 3960:T 3952:T 3941:x 3938:y 3932:. 3926:C 3922:B 3916:) 3906:x 3902:) 3900:T 3897:T 3894:B 3890:T 3885:) 3875:x 3871:) 3869:T 3866:T 3863:C 3859:T 3854:) 3844:x 3840:) 3838:T 3835:T 3832:S 3828:T 3823:) 3821:E 3817:x 3813:] 3811:T 3807:T 3800:I 3796:T 3791:) 3789:E 3785:x 3781:) 3779:T 3776:K 3772:T 3766:) 3764:T 3761:T 3757:T 3750:x 3746:T 3722:S 3718:K 3712:( 3710:S 3708:( 3706:K 3704:( 3702:S 3700:( 3698:S 3694:C 3690:) 3688:K 3682:( 3680:S 3676:B 3669:K 3665:S 3657:x 3654:g 3652:( 3650:f 3646:x 3643:g 3640:f 3637:B 3635:( 3632:) 3630:g 3626:x 3623:f 3619:x 3616:g 3613:f 3610:C 3608:( 3602:C 3598:B 3590:K 3586:S 3571:S 3562:( 3554:K 3541:( 3536:K 3533:S 3530:K 3512:X 3504:X 3500:S 3496:K 3490:. 3488:S 3484:X 3481:X 3479:( 3477:X 3475:( 3473:X 3471:( 3469:X 3463:K 3459:X 3456:X 3454:( 3452:X 3450:( 3448:X 3439:) 3437:K 3435:) 3433:S 3425:X 3418:X 3402:I 3398:x 3395:f 3389:. 3379:I 3373:( 3371:S 3365:( 3363:S 3361:( 3359:S 3355:x 3352:f 3346:. 3340:T 3334:) 3322:K 3320:( 3318:y 3308:K 3306:( 3304:y 3301:I 3296:) 3294:y 3290:x 3287:K 3285:( 3278:) 3276:y 3272:x 3269:K 3267:( 3265:x 3259:( 3257:K 3252:) 3247:K 3241:( 3239:K 3237:( 3235:S 3233:( 3220:K 3214:( 3212:K 3210:( 3208:S 3203:) 3201:T 3195:( 3193:K 3191:( 3189:S 3180:T 3167:E 3163:E 3159:E 3155:x 3151:E 3142:) 3140:E 3136:x 3132:T 3128:T 3117:T 3100:E 3098:. 3092:E 3088:E 3084:E 3080:E 3074:) 3072:T 3069:T 3066:S 3064:( 3058:E 3056:. 3050:E 3048:. 3043:S 3039:E 3035:E 3023:E 3021:. 3015:E 3013:. 3008:S 3004:E 3000:E 2979:) 2977:a 2973:E 2971:. 2964:. 2959:S 2954:) 2952:a 2948:E 2946:. 2940:E 2938:. 2933:S 2920:a 2916:E 2914:. 2908:a 2904:E 2902:. 2896:a 2892:E 2888:E 2882:( 2875:E 2871:E 2867:E 2863:E 2861:( 2855:E 2851:E 2847:x 2843:E 2839:E 2835:a 2831:E 2827:E 2823:x 2819:E 2815:E 2811:a 2807:E 2803:E 2785:E 2781:x 2777:T 2774:K 2770:E 2768:. 2762:I 2758:x 2756:. 2750:T 2743:] 2731:T 2723:n 2721:( 2719:Θ 2715:n 2711:T 2705:. 2699:I 2693:( 2691:S 2685:( 2683:K 2681:( 2679:S 2666:I 2659:I 2657:( 2655:K 2648:I 2644:K 2641:K 2634:I 2630:K 2627:K 2625:( 2623:S 2616:I 2612:K 2609:K 2607:( 2605:S 2601:I 2594:I 2590:K 2587:K 2585:( 2583:S 2581:( 2579:I 2576:S 2569:I 2565:K 2562:K 2560:( 2558:S 2554:I 2551:S 2549:( 2547:K 2540:I 2536:K 2533:K 2531:( 2529:S 2525:I 2522:S 2520:( 2518:K 2516:( 2514:S 2512:( 2506:y 2502:x 2492:I 2486:( 2484:S 2478:( 2476:K 2474:( 2472:S 2465:T 2459:( 2457:S 2451:( 2449:K 2447:( 2445:S 2438:T 2435:T 2432:S 2426:( 2424:K 2422:( 2420:S 2413:T 2407:( 2405:K 2403:( 2401:S 2394:T 2391:T 2388:S 2381:T 2374:T 2367:T 2360:T 2357:T 2350:T 2344:T 2337:x 2334:y 2328:. 2312:) 2304:( 2302:S 2293:( 2289:I 2285:x 2280:y 2277:K 2273:y 2266:E 2258:E 2235:T 2227:E 2223:E 2219:x 2215:) 2213:T 2210:T 2207:S 2203:T 2198:) 2196:E 2192:x 2188:] 2186:T 2182:T 2175:I 2171:T 2166:) 2164:E 2160:x 2156:) 2154:T 2151:K 2147:T 2141:) 2139:T 2136:T 2132:T 2125:x 2121:T 2112:T 2104:T 2095:K 2091:S 2076:Y 2053:I 2025:I 2017:x 2013:x 2010:I 2006:x 1998:x 1989:x 1982:x 1979:K 1977:( 1975:x 1972:K 1967:) 1965:x 1955:x 1943:I 1939:K 1935:S 1928:z 1924:y 1920:x 1916:z 1912:y 1908:x 1904:S 1895:( 1886:S 1884:( 1878:S 1871:x 1867:y 1864:x 1861:K 1859:( 1853:y 1849:x 1842:x 1838:y 1834:x 1831:K 1823:x 1819:x 1816:K 1812:K 1808:x 1801:x 1797:x 1794:I 1792:( 1786:I 1774:} 1771:n 1769:x 1765:1 1762:x 1760:{ 1756:E 1748:E 1743:n 1741:x 1737:1 1734:x 1731:P 1729:( 1702:) 1697:n 1693:E 1689:. 1686:. 1683:. 1680:) 1675:3 1671:E 1667:) 1662:2 1658:E 1652:1 1648:E 1644:( 1641:( 1638:. 1635:. 1632:. 1629:( 1603:n 1599:E 1595:. 1592:. 1589:. 1584:3 1580:E 1574:2 1570:E 1564:1 1560:E 1535:) 1530:n 1526:E 1522:. 1519:. 1516:. 1511:3 1507:E 1501:2 1497:E 1491:1 1487:E 1483:( 1443:S 1439:K 1435:I 1427:P 1416:x 1320:3 1314:3 1287:3 1281:3 1261:x 1218:x 1212:x 1200:x 1172:) 1169:c 1166:) 1163:b 1160:a 1157:( 1154:( 1130:) 1127:c 1124:b 1121:a 1118:( 1091:] 1088:a 1082:v 1079:[ 1076:E 1070:) 1067:a 1064:) 1061:E 1058:. 1055:v 1049:( 1046:( 1031:a 1027:v 1023:E 1007:] 1004:a 998:v 995:[ 992:E 961:) 956:2 952:E 948:) 943:1 939:E 935:. 932:v 926:( 923:( 893:1 889:E 862:1 858:E 831:2 827:E 792:1 788:E 761:2 757:E 730:1 726:E 697:) 692:2 688:E 682:1 678:E 674:( 659:v 641:1 637:E 610:1 606:E 593:v 575:1 571:E 567:. 564:v 531:1 527:E 510:v 488:1 484:E 480:. 477:v 445:2 441:E 414:1 410:E 385:v 358:) 353:2 349:E 343:1 339:E 335:( 308:1 304:E 300:. 297:v 269:v 20:)

Index

Combinatory Logic
combinational logic
quantified
mathematical logic
Moses Schönfinkel
Haskell Curry
computer science
model of computation
functional programming languages
Schönfinkel
predicate logic
higher-order function
function application
quantified variables
Quine's
predicate functor logic
expressive power
first-order logic
predicate functor logic
Quine 1960, 1966, 1976
Moses Schönfinkel
Haskell Curry
Princeton University
Alonzo Church
lambda calculus
Haskell Curry
Robert Feys
Belgium
Barendregt
models

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