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Term (logic)

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1199: 295: 5441: 3249: 700:", denote the same term and correspond to the same tree, viz. the left tree in the above picture. Separating the tree structure of a term from its graphical representation on paper, it is also easy to account for parentheses (being only representation, not structure) and invisible multiplication operators (existing only in structure, not in representation). 1771:
indicated by blue variables immediately left to their black substitutes. Intuitively, the pattern, except for its variables, must be contained in the subject; if a variable occurs multiple times in the pattern, equal subterms are required at the respective positions of the
1347:, can be assigned, that is, a string of natural numbers indicating the node's place in the hierarchy. The empty string, commonly denoted by ε, is assigned to the root node. Position strings within the black term are indicated in red in the picture. 1630:
by some authors) can be assigned, i.e. its distance (number of edges) from the root. In this setting, the depth of a node always equals the length of its position string. In the picture, depth levels in the black term are indicated in
1638:
of a term commonly refers to the number of its nodes, or, equivalently, to the length of the term's written representation, counting symbols without parentheses. The black and the blue term in the picture has the size 15 and 5,
1041: 2885:. The general sum operator Σ can then be considered as a ternary function symbol taking a lower bound value, an upper bound value and a function to be summed-up. Due to its latter argument, the Σ operator is called a 2259: 2839: 2769: 2098: 1291: 2044: 2157: 2627: 1609: 732:. While structural equality can be checked without any knowledge about the meaning of the symbols, semantic equality cannot. If the function / is e.g. interpreted not as rational but as 1539: 1186:. An atomic formula is called ground if it is built entirely from ground terms; all ground atomic formulas composable from a given set of function and predicate symbols make up the 2533: 1968: 698: 259: 2373: 3820: 2333: 2294: 1172: 1138: 147: 4495: 1743: 1331: 199: 175: 4578: 3719: 632:
became popular in computer science, it turned out to be more convenient to think of a term as a tree. For example, several distinct character strings, like "
1615:
and embedding are converse to each other: while the former appends function symbols at the bottom of the term, the latter appends them at the top. The
1802:
When the domain of discourse contains elements of basically different kinds, it is useful to split the set of all terms accordingly. To this end, a
1059:-ary root function symbol. The sum has a finite value if there is only a finite number of constants and function symbols, which is usually the case. 961: 4892: 2936:
The rightmost column of the table indicates how each mathematical notation example can be represented by a lambda term, also converting common
5050: 3622: 3838: 2181: 4905: 4228: 4490: 4910: 4900: 4637: 3843: 1810:) is assigned to each variable and each constant symbol, and a declaration of domain sorts and range sort to each function symbol. A 4388: 3834: 787:. In many contexts, the particular variable names in a term don't matter, e.g. the commutativity axiom for addition can be stated as 5046: 46:
denotes a mathematical fact. In particular, terms appear as components of a formula. This is analogous to natural language, where a
523:
and higher-arity functions are possible but uncommon in practice. Many authors consider constant symbols as 0-ary function symbols
5143: 4887: 3712: 3482:) formulas can be renamed in a similar way as terms. In fact, some authors consider a quantifier-free formula as a term (of type 4448: 4141: 3882: 3478:
Since atomic formulas can be viewed as trees, too, and renaming is essentially a concept on trees, atomic (and, more generally,
5475: 294: 5404: 5106: 4869: 4864: 4689: 4110: 3794: 3676: 1775: 740:=2 the left and right term evaluates to 3 and 2, respectively. Structural equal terms need to agree in their variable names. 2844:
All these operators can be viewed as taking a function rather than a value term as one of their arguments. For example, the
2778: 2708: 1198: 5399: 5182: 5099: 4812: 4743: 4620: 3862: 720:
equal if they correspond to the same tree. For example, the left and the right tree in the above picture are structurally
4470: 5324: 5150: 4836: 4069: 2053: 1205: 43: 4475: 2848:
operator is applied to a sequence, i.e. to a mapping from positive integer to e.g. real numbers. As another example, a
1987: 5465: 4807: 4546: 3804: 3705: 5202: 5197: 2852:
function to implement the second example from the table, Σ, would have a function pointer argument (see box below).
2105: 5470: 5131: 4721: 4115: 4083: 3774: 2573: 3848: 1551: 5421: 5370: 5267: 4765: 4726: 4203: 5262: 3877: 1477: 5192: 4731: 4583: 4566: 4289: 3769: 3508: 3459: 2849: 5094: 5071: 5032: 4918: 4859: 4505: 4425: 4269: 4213: 3826: 3479: 70: 5384: 5111: 5089: 5056: 4949: 4795: 4780: 4753: 4704: 4588: 4523: 4348: 4314: 4309: 4183: 4014: 3991: 2490: 1616: 94: 90: 66: 51: 2693:
Mathematical notations as shown in the table do not fit into the scheme of a first-order term as defined
1931: 659: 5314: 5167: 4959: 4677: 4413: 4319: 4178: 4163: 4044: 4019: 629: 608:
by the first, second, and third term building rule, respectively. The latter term is usually written as
5440: 208: 2340: 5287: 5249: 5126: 4930: 4770: 4694: 4672: 4500: 4458: 4357: 4324: 4188: 3976: 3887: 1612: 768: 351: 62: 5416: 5307: 5292: 5272: 5229: 5116: 5066: 4992: 4937: 4874: 4667: 4662: 4610: 4378: 4367: 4039: 3939: 3867: 3858: 3854: 3789: 3784: 1881: 819:; in such cases the whole formula may be renamed, while an arbitrary subterm usually may not, e.g. 534: 39: 2303: 2264: 1155: 1121: 5445: 5214: 5177: 5162: 5155: 5138: 4924: 4790: 4716: 4699: 4652: 4465: 4374: 4208: 4193: 4153: 4105: 4090: 4078: 4034: 4009: 3779: 3728: 2862: 1387: 1115: 1111: 102: 31: 4942: 4398: 5380: 5187: 4997: 4987: 4879: 4760: 4595: 4571: 4352: 4336: 4241: 4218: 4095: 4064: 4029: 3924: 3759: 3682: 3672: 3645: 3618: 3589: 2385: 1797: 1187: 1107: 889: 520: 485: 442: 279: 74: 58: 1710: 1298: 5394: 5389: 5282: 5239: 5061: 5022: 5017: 5002: 4828: 4785: 4682: 4480: 4430: 4004: 3966: 3641: 733: 283: 1982:, and the vector addition, the scalar multiplication, and the inner product is declared as 5375: 5365: 5319: 5302: 5257: 5219: 5121: 5041: 4848: 4775: 4748: 4736: 4642: 4556: 4530: 4485: 4453: 4254: 4056: 3999: 3949: 3914: 3872: 3504: 2941: 903: 729: 5360: 5339: 5297: 5277: 5172: 5027: 4625: 4615: 4605: 4600: 4534: 4408: 4284: 4173: 4168: 4146: 3747: 2937: 1780: 1183: 882: 759:
if the latter resulted from consistently renaming all variables of the former, i.e. if
613: 184: 160: 78: 3248: 5459: 5334: 5012: 4519: 4304: 4294: 4264: 4249: 3919: 3610: 1383: 86: 5234: 5081: 4982: 4974: 4854: 4711: 4647: 4630: 4561: 4420: 4279: 3981: 3764: 3606: 3123:// implements anonymous function (lambda i. i*i); however, C requires a name for it 1877: 897: 3652:. Studies in Logic and the Foundation of Mathematics. Vol. 73. North Holland. 5344: 5224: 4403: 4393: 4340: 4024: 3944: 3929: 3809: 3754: 3664: 3283:
of variable symbols, the set of lambda terms is defined recursively as follows:
2856: 2683: 1141: 894: 857: 264: 47: 17: 4274: 4129: 4100: 3906: 3686: 1747:
matches the black subject term at position 1, with the matching substitution
1431:
can also be viewed as resulting from a generalized concatenation of the term
1374:. For example, at position 122 of the black term in the picture, the subterm 1036:{\displaystyle \theta _{h+1}=\sum _{i=0}^{\infty }f_{i}\cdot \theta _{h}^{i}} 861:; a term that doesn't contain multiple occurrences of a variable is called a 342:-ary function symbols, also called operator symbols, for each natural number 5426: 5329: 4382: 4299: 4259: 4223: 4159: 3971: 3961: 3934: 1339:
Since a term has the structure of a tree hierarchy, to each of its nodes a
881:+1) is a non-linear term. These properties are important in, for example, 5411: 5209: 4657: 4362: 3956: 3454: 2914: 1085:≥ 1, an (unsorted first-order) atomic formula is obtained by applying an 5007: 3799: 1182:+1) ≥ 0 is a mathematical formula evaluating to true in the algebra of 2877:
from the C program below can be written anonymously as a lambda term λ
2771:
doesn't make sense. In contrast, the other variables, referred to as
2254:{\displaystyle \langle ({\vec {v}}+{\vec {0}})*a,{\vec {w}}*b\rangle } 3697: 2377:
is required. Function symbols having several declarations are called
2933:
operator takes such a sequence and returns its limit (if defined).
4551: 3897: 3742: 2705:, variable that may not appear outside the notation's scope, e.g. 1197: 865:. For example, 2+2 is a ground term and hence also a linear term, 628:
adhering to certain building rules. However, since the concept of
558: 497:
are inhabited. Well-known examples are the unary function symbols
275: 82: 3360:, etc. which are, however, not admitted in pure lambda calculus. 1928:
the set of vector and number constants, respectively. Then e.g.
3701: 3243: 1910:
be the set of vector and number variables, respectively, and
779:, too, since a renaming substitution σ has an inverse σ, and 3352:
The above motivating examples also used some constants like
892:
for the function symbols, the set of all terms forms the
1892:
denote the sort of vectors and numbers, respectively, let
488:
of the term language describes which function symbol sets
956:, since a ground term of height 0 can only be a constant, 855:). A term that doesn't contain any variables is called a 2775:, behave like ordinary first-order term variables, e.g. 1541:. The latter term also results from embedding the term 3260: 1619:
relates a term and any result of appends on both sides.
616:
and the more common operator symbol + for convenience.
3617:. Cambridge University Press. pp. 1–2 and 34–35. 2834:{\displaystyle k\cdot \int _{a}^{b}\sin(k\cdot t)\;dt} 2764:{\displaystyle t\cdot \int _{a}^{b}\sin(k\cdot t)\;dt} 1705:, respectively. In the picture, the blue pattern term 1093:
terms. As for function symbols, a relation symbol set
354:
to be the smallest set with the following properties:
3503:
Renaming of the commutativity axiom can be viewed as
2781: 2711: 2576: 2493: 2343: 2306: 2267: 2184: 2108: 2056: 1990: 1934: 1713: 1554: 1480: 1301: 1208: 1158: 1124: 964: 662: 211: 187: 163: 105: 941:
can be computed by the following recursion formula:
541:
denotes a named object from that domain, a variable
530:, thus needing no special syntactic class for them. 5353: 5248: 5080: 4973: 4825: 4518: 4441: 4335: 4239: 4128: 4055: 3990: 3905: 3896: 3818: 3735: 835:is not a valid version of the commutativity axiom. 2833: 2763: 2621: 2527: 2388:for more information, including extensions of the 2367: 2327: 2288: 2253: 2151: 2093:{\displaystyle \langle .,.\rangle :W\times W\to N} 2092: 2038: 1962: 1737: 1603: 1533: 1325: 1286:{\displaystyle {\frac {a*((a+1)*(a+2))}{1*(2*3)}}} 1285: 1166: 1132: 1035: 692: 253: 193: 169: 151:is a term built from the constant 1, the variable 141: 2039:{\displaystyle +:W\times W\to W,*:W\times N\to W} 1390:since each term is trivially a subterm of itself. 724:equal terms, although they might be considered " 3422:denotes the constant function always returning 2913:/3, ..., respectively, that is, it denotes the 728:" as they always evaluate to the same value in 545:ranges over the objects in that domain, and an 512:, and the binary function symbols +, −, ⋅, / ∈ 77:to an appropriate number of terms is called an 27:Components of a mathematical or logical formula 2335:a well-sorted term, an additional declaration 2296:is not (since + doesn't accept a term of sort 2152:{\displaystyle {\vec {v}},{\vec {w}}\in V_{W}} 1081:-ary relation symbols for each natural number 533:A term denotes a mathematical object from the 3713: 3392:) denotes the result of calling the function 2901:denotes a function that maps 1, 2, 3, ... to 2622:{\displaystyle \int _{a}^{b}\sin(k\cdot t)dt} 624:Originally, logicians defined a term to be a 346:≥ 1, the set of (unsorted first-order) terms 8: 2248: 2185: 2069: 2057: 1604:{\displaystyle {\frac {a*(\;.\;)}{1*(2*3)}}} 937:of distinct ground terms of a height up to 4539: 4134: 3902: 3720: 3706: 3698: 2824: 2754: 2102:, respectively. Assuming variable symbols 1611:. In an informal sense, the operations of 1571: 1567: 1534:{\displaystyle {\frac {a*(b+1)}{1*(2*3)}}} 783:= uσ. Both terms are then also said to be 3592:section of the Signature (logic) article. 3222:// applies sum operator to sum up squares 2797: 2792: 2780: 2727: 2722: 2710: 2586: 2581: 2575: 2519: 2509: 2498: 2492: 2342: 2314: 2313: 2305: 2269: 2268: 2266: 2231: 2230: 2207: 2206: 2192: 2191: 2183: 2143: 2125: 2124: 2110: 2109: 2107: 2055: 1989: 1954: 1936: 1935: 1933: 1712: 1555: 1553: 1481: 1479: 1300: 1209: 1207: 1160: 1159: 1157: 1126: 1125: 1123: 1027: 1022: 1009: 999: 988: 969: 963: 663: 661: 210: 186: 162: 104: 2399: 911:Abbreviating the number of constants as 901:. The set of all ground terms forms the 445:notation, this is sometimes written as: 293: 3633: 3471: 2889:. As another example, the lambda term λ 1853:th subterm's sort matches the declared 1833:) may be composed from sorted subterms 1685:and some substitution σ. In this case, 1465:is the black term in the picture, then 561:of objects to objects. For example, if 3414:denotes the identity function, while λ 3371:denotes a unary function that returns 3348:) is also a lambda term (application). 2694: 1866: 1449:(indicated by "."; its position being 1106:. In mathematical logic, more complex 1043:, since a ground term of height up to 1362:starts, which is commonly denoted by 1202:Tree structure of black example term 1110:are built from atomic formulas using 73:. An expression formed by applying a 7: 3318:is also a lambda term (abstraction); 2528:{\displaystyle \sum _{i=1}^{n}i^{2}} 1102:is usually non-empty only for small 1047:+1 can be obtained by composing any 3441:and returns the result of applying 2300:as 2nd argument). In order to make 1963:{\displaystyle {\vec {0}}\in C_{W}} 1865:; any other term (i.e. obeying the 693:{\displaystyle {\frac {n(n+1)}{2}}} 203:; it is part of the atomic formula 3669:Introduction to Mathematical Logic 2994:// implements general sum operator 1000: 584:is a binary function symbol, then 155:, and the binary function symbols 25: 3576: 3491: 1657:structurally equals a subterm of 620:Term structure vs. representation 369:every constant symbol is a term: 358:every variable symbol is a term: 263:which evaluates to true for each 254:{\displaystyle (x+1)*(x+1)\geq 0} 5439: 3406:. For example, the abstraction λ 3247: 2368:{\displaystyle *:N\times W\to W} 1653:, if a substitution instance of 278:, terms play important roles in 50:refers to an object and a whole 2866:to be supplied as arguments to 2697:, as they all introduce an own 843:The set of variables of a term 3363:Intuitively, the abstraction λ 2821: 2809: 2751: 2739: 2610: 2598: 2359: 2319: 2274: 2236: 2218: 2212: 2197: 2188: 2130: 2115: 2084: 2030: 2006: 1941: 1732: 1720: 1595: 1583: 1572: 1564: 1525: 1513: 1502: 1490: 1378:+2 has its root. The relation 1320: 1308: 1277: 1265: 1254: 1251: 1239: 1233: 1221: 1218: 681: 669: 242: 230: 224: 212: 136: 124: 118: 106: 1: 5400:History of mathematical logic 1861:. Such a term is also called 1051:ground terms of height up to 329:of constant symbols and sets 5325:Primitive recursive function 3551:", which is synonymous to "∀ 2887:second-order function symbol 2328:{\displaystyle a*{\vec {v}}} 2289:{\displaystyle {\vec {v}}+a} 1622:To each node of a term, its 1167:{\displaystyle \mathbb {R} } 1133:{\displaystyle \mathbb {R} } 1064:Building formulas from terms 301:tree structure of the term ( 3615:Term Rewriting and All That 3588:I.e., "symbol type" in the 2401:Terms with bound variables 1386:on the set of terms; it is 441:Using an intuitive, pseudo- 325:of variable symbols, a set 142:{\displaystyle (x+1)*(x+1)} 5492: 4389:Schröder–Bernstein theorem 4116:Monadic predicate calculus 3775:Foundations of mathematics 3379:, while the application ( 2873:For example, the function 2681: 1795: 1401:the subterm at a position 573:is a constant symbol, and 569:is a variable symbol, 1 ∈ 5435: 5422:Philosophy of mathematics 5371:Automated theorem proving 4542: 4496:Von Neumann–Bernays–Gödel 4137: 3335:are lambda terms, then ( 3306:is a variable symbol and 1880:comes with an associated 1441:; the latter is called a 922:-ary function symbols as 708:Two terms are said to be 3460:Expression (mathematics) 3310:is a lambda term, then λ 2946: 1435:with a term-like object 1089:-ary relation symbol to 5072:Self-verifying theories 4893:Tarski's axiomatization 3844:Tarski's undefinability 3839:incompleteness theorems 1884:of scalar numbers. Let 1806:(sometimes also called 1738:{\displaystyle x*(y*z)} 1693:, and σ are called the 1409:is commonly denoted by 1326:{\displaystyle x*(y*z)} 1190:for these symbol sets. 1118:. For example, letting 839:Ground and linear terms 65:from constant symbols, 63:recursively constructed 5476:Elementary mathematics 5446:Mathematics portal 5057:Proof of impossibility 4705:propositional variable 4015:Propositional calculus 3590:Many-sorted signatures 3287:every variable symbol 2860:can be used to denote 2835: 2765: 2623: 2529: 2514: 2369: 2329: 2290: 2261:is well-sorted, while 2255: 2153: 2094: 2040: 1964: 1739: 1617:encompassment ordering 1605: 1535: 1335: 1327: 1287: 1168: 1134: 1037: 1004: 873:+1) is a linear term, 694: 318: 255: 195: 171: 143: 5315:Kolmogorov complexity 5268:Computably enumerable 5168:Model complete theory 4960:Principia Mathematica 4020:Propositional formula 3849:Banach–Tarski paradox 2836: 2766: 2624: 2530: 2494: 2390:many-sorted framework 2370: 2330: 2291: 2256: 2154: 2095: 2041: 1965: 1740: 1703:matching substitution 1606: 1536: 1393:The term obtained by 1328: 1288: 1201: 1194:Operations with terms 1169: 1135: 1038: 984: 785:equal modulo renaming 769:renaming substitution 695: 404:-ary function symbol 297: 256: 196: 172: 144: 81:, which evaluates to 5263:Church–Turing thesis 5250:Computability theory 4459:continuum hypothesis 3977:Square of opposition 3835:Gödel's completeness 2779: 2709: 2574: 2491: 2341: 2304: 2265: 2182: 2106: 2054: 1988: 1932: 1711: 1552: 1478: 1474:results in the term 1299: 1206: 1156: 1122: 962: 918:, and the number of 743:In contrast, a term 660: 209: 185: 161: 103: 5417:Mathematical object 5308:P versus NP problem 5273:Computable function 5067:Reverse mathematics 4993:Logical consequence 4870:primitive recursive 4865:elementary function 4638:Free/bound variable 4491:Tarski–Grothendieck 4010:Logical connectives 3940:Logical equivalence 3790:Logical consequence 3691:; here: Sect.II.1.3 3671:. Springer London. 3527:" actually means "∀ 3437:) takes a function 3426:. The lambda term λ 2863:anonymous functions 2802: 2732: 2591: 2402: 1112:logical connectives 1032: 730:rational arithmetic 704:Structural equality 535:domain of discourse 352:recursively defined 40:mathematical object 5466:Mathematical logic 5215:Transfer principle 5178:Semantics of logic 5163:Categorical theory 5139:Non-standard model 4653:Logical connective 3780:Information theory 3729:Mathematical logic 3259:. You can help by 2831: 2788: 2761: 2718: 2619: 2577: 2525: 2400: 2365: 2325: 2286: 2251: 2149: 2090: 2036: 1960: 1857:th domain sort of 1735: 1677:for some position 1661:, or formally, if 1601: 1531: 1461:. For example, if 1336: 1323: 1293:, with blue redex 1283: 1164: 1140:denote the set of 1130: 1033: 1018: 736:division, then at 734:truncating integer 726:semantically equal 690: 521:Ternary operations 319: 251: 191: 167: 139: 54:refers to a fact. 32:mathematical logic 5471:Rewriting systems 5453: 5452: 5385:Abstract category 5188:Theories of truth 4998:Rule of inference 4988:Natural deduction 4969: 4968: 4514: 4513: 4219:Cartesian product 4124: 4123: 4030:Many-valued logic 4005:Boolean functions 3888:Russell's paradox 3863:diagonal argument 3760:First-order logic 3646:H. Jerome Keisler 3624:978-0-521-77920-3 3509:universal closure 3486:rather than e.g. 3295:is a lambda term; 3277: 3276: 2841:does make sense. 2680: 2679: 2386:many-sorted logic 2322: 2277: 2239: 2215: 2200: 2133: 2118: 1944: 1798:Many-sorted logic 1599: 1548:into the context 1529: 1380:"is a subterm of" 1350:At each position 1281: 775:is a renaming of 771:σ. In that case, 688: 290:Formal definition 284:rewriting systems 280:universal algebra 194:{\displaystyle *} 170:{\displaystyle +} 16:(Redirected from 5483: 5444: 5443: 5395:History of logic 5390:Category of sets 5283:Decision problem 5062:Ordinal analysis 5003:Sequent calculus 4901:Boolean algebras 4841: 4840: 4815: 4786:logical/constant 4540: 4526: 4449:Zermelo–Fraenkel 4200:Set operations: 4135: 4072: 3903: 3883:Löwenheim–Skolem 3770:Formal semantics 3722: 3715: 3708: 3699: 3692: 3690: 3661: 3655: 3654:; here: Sect.1.3 3653: 3638: 3628: 3593: 3586: 3580: 3505:alpha-conversion 3501: 3495: 3476: 3272: 3269: 3251: 3244: 3235: 3232: 3229: 3226: 3223: 3220: 3217: 3214: 3211: 3208: 3205: 3202: 3199: 3196: 3193: 3190: 3187: 3184: 3181: 3178: 3175: 3172: 3169: 3166: 3163: 3160: 3157: 3154: 3151: 3148: 3145: 3142: 3139: 3136: 3133: 3130: 3127: 3124: 3121: 3118: 3115: 3112: 3109: 3106: 3103: 3100: 3097: 3094: 3091: 3088: 3085: 3082: 3079: 3076: 3073: 3070: 3067: 3064: 3061: 3058: 3055: 3052: 3049: 3046: 3043: 3040: 3037: 3034: 3031: 3028: 3025: 3022: 3019: 3016: 3013: 3010: 3007: 3004: 3001: 2998: 2995: 2992: 2989: 2986: 2983: 2980: 2977: 2974: 2971: 2968: 2965: 2962: 2959: 2956: 2953: 2950: 2840: 2838: 2837: 2832: 2801: 2796: 2770: 2768: 2767: 2762: 2731: 2726: 2628: 2626: 2625: 2620: 2590: 2585: 2534: 2532: 2531: 2526: 2524: 2523: 2513: 2508: 2451: 2443: 2442: 2441: 2440: 2433: 2403: 2392:described here. 2376: 2374: 2372: 2371: 2366: 2334: 2332: 2331: 2326: 2324: 2323: 2315: 2295: 2293: 2292: 2287: 2279: 2278: 2270: 2260: 2258: 2257: 2252: 2241: 2240: 2232: 2217: 2216: 2208: 2202: 2201: 2193: 2177: 2158: 2156: 2155: 2150: 2148: 2147: 2135: 2134: 2126: 2120: 2119: 2111: 2101: 2099: 2097: 2096: 2091: 2047: 2045: 2043: 2042: 2037: 1981: 1969: 1967: 1966: 1961: 1959: 1958: 1946: 1945: 1937: 1869:only) is called 1856: 1852: 1787:Related concepts 1770: 1746: 1744: 1742: 1741: 1736: 1676: 1610: 1608: 1607: 1602: 1600: 1598: 1575: 1556: 1547: 1540: 1538: 1537: 1532: 1530: 1528: 1505: 1482: 1473: 1447:term with a hole 1440: 1430: 1419: 1373: 1334: 1332: 1330: 1329: 1324: 1292: 1290: 1289: 1284: 1282: 1280: 1257: 1210: 1173: 1171: 1170: 1165: 1163: 1139: 1137: 1136: 1131: 1129: 1042: 1040: 1039: 1034: 1031: 1026: 1014: 1013: 1003: 998: 980: 979: 699: 697: 696: 691: 689: 684: 664: 655: 643: 626:character string 417:, a larger term 270: 262: 260: 258: 257: 252: 202: 200: 198: 197: 192: 178: 176: 174: 173: 168: 154: 150: 148: 146: 145: 140: 75:predicate symbol 71:function symbols 21: 5491: 5490: 5486: 5485: 5484: 5482: 5481: 5480: 5456: 5455: 5454: 5449: 5438: 5431: 5376:Category theory 5366:Algebraic logic 5349: 5320:Lambda calculus 5258:Church encoding 5244: 5220:Truth predicate 5076: 5042:Complete theory 4965: 4834: 4830: 4826: 4821: 4813: 4533: and  4529: 4524: 4510: 4486:New Foundations 4454:axiom of choice 4437: 4399:Gödel numbering 4339: and  4331: 4235: 4120: 4070: 4051: 4000:Boolean algebra 3986: 3950:Equiconsistency 3915:Classical logic 3892: 3873:Halting problem 3861: and  3837: and  3825: and  3824: 3819:Theorems ( 3814: 3731: 3726: 3696: 3695: 3679: 3663: 3662: 3658: 3640: 3639: 3635: 3625: 3605: 3602: 3597: 3596: 3587: 3583: 3511:of the axiom: " 3502: 3498: 3480:quantifier-free 3477: 3473: 3468: 3451: 3405: 3399:with the input 3398: 3391: 3385: 3347: 3341: 3334: 3327: 3273: 3267: 3264: 3257:needs expansion 3242: 3237: 3236: 3233: 3230: 3227: 3224: 3221: 3218: 3215: 3212: 3209: 3206: 3203: 3200: 3197: 3194: 3191: 3188: 3185: 3182: 3179: 3176: 3173: 3170: 3167: 3165:" %d" 3164: 3161: 3158: 3155: 3152: 3149: 3146: 3143: 3140: 3137: 3134: 3131: 3129:<stdio.h> 3128: 3125: 3122: 3119: 3116: 3113: 3110: 3107: 3104: 3101: 3098: 3095: 3092: 3089: 3086: 3083: 3080: 3077: 3074: 3071: 3068: 3065: 3062: 3059: 3056: 3053: 3050: 3047: 3044: 3041: 3038: 3035: 3032: 3029: 3026: 3023: 3020: 3017: 3014: 3011: 3008: 3005: 3002: 2999: 2996: 2993: 2990: 2987: 2984: 2981: 2978: 2975: 2972: 2969: 2966: 2963: 2960: 2957: 2954: 2951: 2948: 2940:operators into 2777: 2776: 2707: 2706: 2691: 2686: 2572: 2571: 2515: 2489: 2488: 2435: 2434: 2431: 2430: 2429: 2428: 2422: 2417: 2412: 2407: 2398: 2339: 2338: 2336: 2302: 2301: 2263: 2262: 2180: 2179: 2176: 2160: 2139: 2104: 2103: 2052: 2051: 2049: 1986: 1985: 1983: 1980: 1971: 1950: 1930: 1929: 1927: 1918: 1909: 1900: 1876:For example, a 1854: 1850: 1848: 1839: 1832: 1823: 1800: 1794: 1789: 1748: 1709: 1708: 1706: 1675: 1662: 1576: 1557: 1550: 1549: 1542: 1506: 1483: 1476: 1475: 1472: 1466: 1436: 1429: 1421: 1418: 1410: 1372: 1363: 1297: 1296: 1294: 1258: 1211: 1204: 1203: 1196: 1184:complex numbers 1154: 1153: 1120: 1119: 1101: 1076: 1066: 1005: 965: 960: 959: 955: 948: 936: 930: 917: 841: 706: 665: 658: 657: 645: 633: 622: 583: 529: 518: 511: 496: 479: 470: 437:) can be built. 436: 427: 416: 399: 390: 337: 292: 268: 207: 206: 204: 183: 182: 180: 159: 158: 156: 152: 101: 100: 98: 97:. For example, 91:bivalent logics 28: 23: 22: 18:Variant (logic) 15: 12: 11: 5: 5489: 5487: 5479: 5478: 5473: 5468: 5458: 5457: 5451: 5450: 5436: 5433: 5432: 5430: 5429: 5424: 5419: 5414: 5409: 5408: 5407: 5397: 5392: 5387: 5378: 5373: 5368: 5363: 5361:Abstract logic 5357: 5355: 5351: 5350: 5348: 5347: 5342: 5340:Turing machine 5337: 5332: 5327: 5322: 5317: 5312: 5311: 5310: 5305: 5300: 5295: 5290: 5280: 5278:Computable set 5275: 5270: 5265: 5260: 5254: 5252: 5246: 5245: 5243: 5242: 5237: 5232: 5227: 5222: 5217: 5212: 5207: 5206: 5205: 5200: 5195: 5185: 5180: 5175: 5173:Satisfiability 5170: 5165: 5160: 5159: 5158: 5148: 5147: 5146: 5136: 5135: 5134: 5129: 5124: 5119: 5114: 5104: 5103: 5102: 5097: 5090:Interpretation 5086: 5084: 5078: 5077: 5075: 5074: 5069: 5064: 5059: 5054: 5044: 5039: 5038: 5037: 5036: 5035: 5025: 5020: 5010: 5005: 5000: 4995: 4990: 4985: 4979: 4977: 4971: 4970: 4967: 4966: 4964: 4963: 4955: 4954: 4953: 4952: 4947: 4946: 4945: 4940: 4935: 4915: 4914: 4913: 4911:minimal axioms 4908: 4897: 4896: 4895: 4884: 4883: 4882: 4877: 4872: 4867: 4862: 4857: 4844: 4842: 4823: 4822: 4820: 4819: 4818: 4817: 4805: 4800: 4799: 4798: 4793: 4788: 4783: 4773: 4768: 4763: 4758: 4757: 4756: 4751: 4741: 4740: 4739: 4734: 4729: 4724: 4714: 4709: 4708: 4707: 4702: 4697: 4687: 4686: 4685: 4680: 4675: 4670: 4665: 4660: 4650: 4645: 4640: 4635: 4634: 4633: 4628: 4623: 4618: 4608: 4603: 4601:Formation rule 4598: 4593: 4592: 4591: 4586: 4576: 4575: 4574: 4564: 4559: 4554: 4549: 4543: 4537: 4520:Formal systems 4516: 4515: 4512: 4511: 4509: 4508: 4503: 4498: 4493: 4488: 4483: 4478: 4473: 4468: 4463: 4462: 4461: 4456: 4445: 4443: 4439: 4438: 4436: 4435: 4434: 4433: 4423: 4418: 4417: 4416: 4409:Large cardinal 4406: 4401: 4396: 4391: 4386: 4372: 4371: 4370: 4365: 4360: 4345: 4343: 4333: 4332: 4330: 4329: 4328: 4327: 4322: 4317: 4307: 4302: 4297: 4292: 4287: 4282: 4277: 4272: 4267: 4262: 4257: 4252: 4246: 4244: 4237: 4236: 4234: 4233: 4232: 4231: 4226: 4221: 4216: 4211: 4206: 4198: 4197: 4196: 4191: 4181: 4176: 4174:Extensionality 4171: 4169:Ordinal number 4166: 4156: 4151: 4150: 4149: 4138: 4132: 4126: 4125: 4122: 4121: 4119: 4118: 4113: 4108: 4103: 4098: 4093: 4088: 4087: 4086: 4076: 4075: 4074: 4061: 4059: 4053: 4052: 4050: 4049: 4048: 4047: 4042: 4037: 4027: 4022: 4017: 4012: 4007: 4002: 3996: 3994: 3988: 3987: 3985: 3984: 3979: 3974: 3969: 3964: 3959: 3954: 3953: 3952: 3942: 3937: 3932: 3927: 3922: 3917: 3911: 3909: 3900: 3894: 3893: 3891: 3890: 3885: 3880: 3875: 3870: 3865: 3853:Cantor's  3851: 3846: 3841: 3831: 3829: 3816: 3815: 3813: 3812: 3807: 3802: 3797: 3792: 3787: 3782: 3777: 3772: 3767: 3762: 3757: 3752: 3751: 3750: 3739: 3737: 3733: 3732: 3727: 3725: 3724: 3717: 3710: 3702: 3694: 3693: 3677: 3656: 3632: 3631: 3630: 3629: 3623: 3601: 3598: 3595: 3594: 3581: 3496: 3470: 3469: 3467: 3464: 3463: 3462: 3457: 3450: 3447: 3403: 3396: 3389: 3383: 3350: 3349: 3345: 3339: 3332: 3325: 3319: 3296: 3275: 3274: 3254: 3252: 3241: 3238: 2947: 2929:/3, ...). The 2830: 2827: 2823: 2820: 2817: 2814: 2811: 2808: 2805: 2800: 2795: 2791: 2787: 2784: 2760: 2757: 2753: 2750: 2747: 2744: 2741: 2738: 2735: 2730: 2725: 2721: 2717: 2714: 2690: 2687: 2682:Main article: 2678: 2677: 2647: 2634: 2629: 2618: 2615: 2612: 2609: 2606: 2603: 2600: 2597: 2594: 2589: 2584: 2580: 2568: 2567: 2545: 2540: 2535: 2522: 2518: 2512: 2507: 2504: 2501: 2497: 2485: 2484: 2462: 2457: 2452: 2425: 2424: 2419: 2414: 2409: 2397: 2394: 2364: 2361: 2358: 2355: 2352: 2349: 2346: 2321: 2318: 2312: 2309: 2285: 2282: 2276: 2273: 2250: 2247: 2244: 2238: 2235: 2229: 2226: 2223: 2220: 2214: 2211: 2205: 2199: 2196: 2190: 2187: 2172: 2146: 2142: 2138: 2132: 2129: 2123: 2117: 2114: 2089: 2086: 2083: 2080: 2077: 2074: 2071: 2068: 2065: 2062: 2059: 2035: 2032: 2029: 2026: 2023: 2020: 2017: 2014: 2011: 2008: 2005: 2002: 1999: 1996: 1993: 1976: 1957: 1953: 1949: 1943: 1940: 1923: 1914: 1905: 1896: 1867:unsorted rules 1844: 1837: 1828: 1821: 1796:Main article: 1793: 1790: 1788: 1785: 1784: 1783: 1781:term rewriting 1778: 1776:unifying terms 1773: 1734: 1731: 1728: 1725: 1722: 1719: 1716: 1671: 1640: 1632: 1620: 1597: 1594: 1591: 1588: 1585: 1582: 1579: 1574: 1570: 1566: 1563: 1560: 1527: 1524: 1521: 1518: 1515: 1512: 1509: 1504: 1501: 1498: 1495: 1492: 1489: 1486: 1470: 1457:is said to be 1425: 1414: 1405:by a new term 1391: 1368: 1348: 1322: 1319: 1316: 1313: 1310: 1307: 1304: 1279: 1276: 1273: 1270: 1267: 1264: 1261: 1256: 1253: 1250: 1247: 1244: 1241: 1238: 1235: 1232: 1229: 1226: 1223: 1220: 1217: 1214: 1195: 1192: 1162: 1128: 1097: 1072: 1065: 1062: 1061: 1060: 1030: 1025: 1021: 1017: 1012: 1008: 1002: 997: 994: 991: 987: 983: 978: 975: 972: 968: 957: 953: 946: 932: 931:, the number θ 926: 915: 883:term rewriting 847:is denoted by 840: 837: 705: 702: 687: 683: 680: 677: 674: 671: 668: 621: 618: 614:infix notation 596:, and (hence) 581: 549:-ary function 527: 516: 509: 492: 482: 481: 475: 468: 439: 438: 432: 425: 412: 395: 388: 378: 367: 333: 299:Left to right: 291: 288: 250: 247: 244: 241: 238: 235: 232: 229: 226: 223: 220: 217: 214: 190: 166: 138: 135: 132: 129: 126: 123: 120: 117: 114: 111: 108: 95:interpretation 79:atomic formula 26: 24: 14: 13: 10: 9: 6: 4: 3: 2: 5488: 5477: 5474: 5472: 5469: 5467: 5464: 5463: 5461: 5448: 5447: 5442: 5434: 5428: 5425: 5423: 5420: 5418: 5415: 5413: 5410: 5406: 5403: 5402: 5401: 5398: 5396: 5393: 5391: 5388: 5386: 5382: 5379: 5377: 5374: 5372: 5369: 5367: 5364: 5362: 5359: 5358: 5356: 5352: 5346: 5343: 5341: 5338: 5336: 5335:Recursive set 5333: 5331: 5328: 5326: 5323: 5321: 5318: 5316: 5313: 5309: 5306: 5304: 5301: 5299: 5296: 5294: 5291: 5289: 5286: 5285: 5284: 5281: 5279: 5276: 5274: 5271: 5269: 5266: 5264: 5261: 5259: 5256: 5255: 5253: 5251: 5247: 5241: 5238: 5236: 5233: 5231: 5228: 5226: 5223: 5221: 5218: 5216: 5213: 5211: 5208: 5204: 5201: 5199: 5196: 5194: 5191: 5190: 5189: 5186: 5184: 5181: 5179: 5176: 5174: 5171: 5169: 5166: 5164: 5161: 5157: 5154: 5153: 5152: 5149: 5145: 5144:of arithmetic 5142: 5141: 5140: 5137: 5133: 5130: 5128: 5125: 5123: 5120: 5118: 5115: 5113: 5110: 5109: 5108: 5105: 5101: 5098: 5096: 5093: 5092: 5091: 5088: 5087: 5085: 5083: 5079: 5073: 5070: 5068: 5065: 5063: 5060: 5058: 5055: 5052: 5051:from ZFC 5048: 5045: 5043: 5040: 5034: 5031: 5030: 5029: 5026: 5024: 5021: 5019: 5016: 5015: 5014: 5011: 5009: 5006: 5004: 5001: 4999: 4996: 4994: 4991: 4989: 4986: 4984: 4981: 4980: 4978: 4976: 4972: 4962: 4961: 4957: 4956: 4951: 4950:non-Euclidean 4948: 4944: 4941: 4939: 4936: 4934: 4933: 4929: 4928: 4926: 4923: 4922: 4920: 4916: 4912: 4909: 4907: 4904: 4903: 4902: 4898: 4894: 4891: 4890: 4889: 4885: 4881: 4878: 4876: 4873: 4871: 4868: 4866: 4863: 4861: 4858: 4856: 4853: 4852: 4850: 4846: 4845: 4843: 4838: 4832: 4827:Example  4824: 4816: 4811: 4810: 4809: 4806: 4804: 4801: 4797: 4794: 4792: 4789: 4787: 4784: 4782: 4779: 4778: 4777: 4774: 4772: 4769: 4767: 4764: 4762: 4759: 4755: 4752: 4750: 4747: 4746: 4745: 4742: 4738: 4735: 4733: 4730: 4728: 4725: 4723: 4720: 4719: 4718: 4715: 4713: 4710: 4706: 4703: 4701: 4698: 4696: 4693: 4692: 4691: 4688: 4684: 4681: 4679: 4676: 4674: 4671: 4669: 4666: 4664: 4661: 4659: 4656: 4655: 4654: 4651: 4649: 4646: 4644: 4641: 4639: 4636: 4632: 4629: 4627: 4624: 4622: 4619: 4617: 4614: 4613: 4612: 4609: 4607: 4604: 4602: 4599: 4597: 4594: 4590: 4587: 4585: 4584:by definition 4582: 4581: 4580: 4577: 4573: 4570: 4569: 4568: 4565: 4563: 4560: 4558: 4555: 4553: 4550: 4548: 4545: 4544: 4541: 4538: 4536: 4532: 4527: 4521: 4517: 4507: 4504: 4502: 4499: 4497: 4494: 4492: 4489: 4487: 4484: 4482: 4479: 4477: 4474: 4472: 4471:Kripke–Platek 4469: 4467: 4464: 4460: 4457: 4455: 4452: 4451: 4450: 4447: 4446: 4444: 4440: 4432: 4429: 4428: 4427: 4424: 4422: 4419: 4415: 4412: 4411: 4410: 4407: 4405: 4402: 4400: 4397: 4395: 4392: 4390: 4387: 4384: 4380: 4376: 4373: 4369: 4366: 4364: 4361: 4359: 4356: 4355: 4354: 4350: 4347: 4346: 4344: 4342: 4338: 4334: 4326: 4323: 4321: 4318: 4316: 4315:constructible 4313: 4312: 4311: 4308: 4306: 4303: 4301: 4298: 4296: 4293: 4291: 4288: 4286: 4283: 4281: 4278: 4276: 4273: 4271: 4268: 4266: 4263: 4261: 4258: 4256: 4253: 4251: 4248: 4247: 4245: 4243: 4238: 4230: 4227: 4225: 4222: 4220: 4217: 4215: 4212: 4210: 4207: 4205: 4202: 4201: 4199: 4195: 4192: 4190: 4187: 4186: 4185: 4182: 4180: 4177: 4175: 4172: 4170: 4167: 4165: 4161: 4157: 4155: 4152: 4148: 4145: 4144: 4143: 4140: 4139: 4136: 4133: 4131: 4127: 4117: 4114: 4112: 4109: 4107: 4104: 4102: 4099: 4097: 4094: 4092: 4089: 4085: 4082: 4081: 4080: 4077: 4073: 4068: 4067: 4066: 4063: 4062: 4060: 4058: 4054: 4046: 4043: 4041: 4038: 4036: 4033: 4032: 4031: 4028: 4026: 4023: 4021: 4018: 4016: 4013: 4011: 4008: 4006: 4003: 4001: 3998: 3997: 3995: 3993: 3992:Propositional 3989: 3983: 3980: 3978: 3975: 3973: 3970: 3968: 3965: 3963: 3960: 3958: 3955: 3951: 3948: 3947: 3946: 3943: 3941: 3938: 3936: 3933: 3931: 3928: 3926: 3923: 3921: 3920:Logical truth 3918: 3916: 3913: 3912: 3910: 3908: 3904: 3901: 3899: 3895: 3889: 3886: 3884: 3881: 3879: 3876: 3874: 3871: 3869: 3866: 3864: 3860: 3856: 3852: 3850: 3847: 3845: 3842: 3840: 3836: 3833: 3832: 3830: 3828: 3822: 3817: 3811: 3808: 3806: 3803: 3801: 3798: 3796: 3793: 3791: 3788: 3786: 3783: 3781: 3778: 3776: 3773: 3771: 3768: 3766: 3763: 3761: 3758: 3756: 3753: 3749: 3746: 3745: 3744: 3741: 3740: 3738: 3734: 3730: 3723: 3718: 3716: 3711: 3709: 3704: 3703: 3700: 3688: 3684: 3680: 3674: 3670: 3666: 3660: 3657: 3651: 3647: 3643: 3637: 3634: 3626: 3620: 3616: 3612: 3611:Tobias Nipkow 3608: 3604: 3603: 3599: 3591: 3585: 3582: 3578: 3577:#Lambda terms 3574: 3570: 3566: 3562: 3558: 3554: 3550: 3546: 3542: 3538: 3534: 3530: 3526: 3522: 3518: 3514: 3510: 3506: 3500: 3497: 3493: 3492:#Sorted terms 3489: 3485: 3481: 3475: 3472: 3465: 3461: 3458: 3456: 3453: 3452: 3448: 3446: 3444: 3440: 3436: 3433: 3429: 3425: 3421: 3417: 3413: 3409: 3402: 3395: 3388: 3382: 3378: 3374: 3370: 3366: 3361: 3359: 3355: 3344: 3338: 3331: 3324: 3320: 3317: 3313: 3309: 3305: 3301: 3297: 3294: 3290: 3286: 3285: 3284: 3282: 3271: 3262: 3258: 3255:This section 3253: 3250: 3246: 3245: 3239: 2945: 2943: 2939: 2934: 2932: 2928: 2924: 2920: 2916: 2912: 2908: 2904: 2900: 2896: 2892: 2888: 2884: 2880: 2876: 2871: 2870:, Σ, ∫, etc. 2869: 2865: 2864: 2859: 2858: 2853: 2851: 2847: 2842: 2828: 2825: 2818: 2815: 2812: 2806: 2803: 2798: 2793: 2789: 2785: 2782: 2774: 2758: 2755: 2748: 2745: 2742: 2736: 2733: 2728: 2723: 2719: 2715: 2712: 2704: 2700: 2696: 2688: 2685: 2675: 2671: 2667: 2663: 2659: 2655: 2651: 2648: 2646: 2642: 2638: 2635: 2633: 2630: 2616: 2613: 2607: 2604: 2601: 2595: 2592: 2587: 2582: 2578: 2570: 2569: 2565: 2561: 2557: 2553: 2549: 2546: 2544: 2541: 2539: 2536: 2520: 2516: 2510: 2505: 2502: 2499: 2495: 2487: 2486: 2482: 2478: 2474: 2470: 2466: 2463: 2461: 2458: 2456: 2453: 2450: 2446: 2438: 2427: 2426: 2420: 2415: 2410: 2405: 2404: 2395: 2393: 2391: 2387: 2382: 2380: 2362: 2356: 2353: 2350: 2347: 2344: 2316: 2310: 2307: 2299: 2283: 2280: 2271: 2245: 2242: 2233: 2227: 2224: 2221: 2209: 2203: 2194: 2175: 2171: 2167: 2163: 2144: 2140: 2136: 2127: 2121: 2112: 2087: 2081: 2078: 2075: 2072: 2066: 2063: 2060: 2033: 2027: 2024: 2021: 2018: 2015: 2012: 2009: 2003: 2000: 1997: 1994: 1991: 1979: 1975: 1955: 1951: 1947: 1938: 1926: 1922: 1917: 1913: 1908: 1904: 1899: 1895: 1891: 1887: 1883: 1879: 1874: 1872: 1868: 1864: 1860: 1847: 1843: 1836: 1831: 1827: 1820: 1816: 1813: 1809: 1805: 1799: 1791: 1786: 1782: 1779: 1777: 1774: 1768: 1764: 1760: 1756: 1752: 1729: 1726: 1723: 1717: 1714: 1704: 1700: 1696: 1692: 1688: 1684: 1680: 1674: 1669: 1665: 1660: 1656: 1652: 1648: 1645: 1641: 1639:respectively. 1637: 1633: 1629: 1625: 1621: 1618: 1614: 1613:instantiating 1592: 1589: 1586: 1580: 1577: 1568: 1561: 1558: 1545: 1522: 1519: 1516: 1510: 1507: 1499: 1496: 1493: 1487: 1484: 1469: 1464: 1460: 1456: 1452: 1448: 1444: 1439: 1434: 1428: 1424: 1417: 1413: 1408: 1404: 1400: 1396: 1392: 1389: 1385: 1384:partial order 1381: 1377: 1371: 1366: 1361: 1357: 1353: 1349: 1346: 1342: 1338: 1337: 1317: 1314: 1311: 1305: 1302: 1274: 1271: 1268: 1262: 1259: 1248: 1245: 1242: 1236: 1230: 1227: 1224: 1215: 1212: 1200: 1193: 1191: 1189: 1188:Herbrand base 1185: 1181: 1177: 1151: 1147: 1143: 1117: 1113: 1109: 1105: 1100: 1096: 1092: 1088: 1084: 1080: 1075: 1071: 1063: 1058: 1054: 1050: 1046: 1028: 1023: 1019: 1015: 1010: 1006: 995: 992: 989: 985: 981: 976: 973: 970: 966: 958: 952: 944: 943: 942: 940: 935: 929: 925: 921: 914: 909: 907: 905: 900: 899: 896: 891: 886: 884: 880: 876: 872: 868: 864: 860: 859: 854: 850: 846: 838: 836: 834: 830: 826: 822: 818: 814: 810: 806: 802: 798: 794: 790: 786: 782: 778: 774: 770: 766: 762: 758: 754: 750: 746: 741: 739: 735: 731: 727: 723: 719: 718:syntactically 715: 711: 703: 701: 685: 678: 675: 672: 666: 653: 649: 641: 637: 631: 627: 619: 617: 615: 611: 607: 603: 599: 595: 591: 587: 580: 576: 572: 568: 564: 560: 556: 552: 548: 544: 540: 537:. A constant 536: 531: 526: 522: 515: 508: 504: 500: 495: 491: 487: 478: 474: 467: 463: 459: 455: 451: 448: 447: 446: 444: 435: 431: 424: 420: 415: 411: 407: 403: 398: 394: 387: 383: 379: 376: 372: 368: 365: 361: 357: 356: 355: 353: 349: 345: 341: 336: 332: 328: 324: 316: 312: 308: 304: 300: 296: 289: 287: 285: 281: 277: 272: 266: 265:real-numbered 248: 245: 239: 236: 233: 227: 221: 218: 215: 188: 164: 133: 130: 127: 121: 115: 112: 109: 96: 92: 88: 84: 80: 76: 72: 68: 64: 60: 55: 53: 49: 45: 41: 37: 33: 19: 5437: 5235:Ultraproduct 5082:Model theory 5047:Independence 4983:Formal proof 4975:Proof theory 4958: 4931: 4888:real numbers 4860:second-order 4802: 4771:Substitution 4648:Metalanguage 4589:conservative 4562:Axiom schema 4506:Constructive 4476:Morse–Kelley 4442:Set theories 4421:Aleph number 4414:inaccessible 4320:Grothendieck 4204:intersection 4091:Higher-order 4079:Second-order 4025:Truth tables 3982:Venn diagram 3765:Formal proof 3668: 3665:Hermes, Hans 3659: 3650:Model Theory 3649: 3636: 3614: 3607:Franz Baader 3584: 3575:"; see also 3572: 3568: 3564: 3560: 3556: 3552: 3548: 3544: 3540: 3536: 3532: 3528: 3524: 3520: 3516: 3512: 3499: 3487: 3483: 3474: 3442: 3438: 3434: 3431: 3427: 3423: 3419: 3415: 3411: 3407: 3400: 3393: 3386: 3380: 3376: 3372: 3368: 3364: 3362: 3357: 3353: 3351: 3342: 3336: 3329: 3322: 3315: 3311: 3307: 3303: 3299: 3292: 3288: 3280: 3279:Given a set 3278: 3265: 3261:adding to it 3256: 2935: 2930: 2926: 2922: 2918: 2910: 2906: 2902: 2898: 2894: 2890: 2886: 2882: 2878: 2874: 2872: 2867: 2861: 2857:Lambda terms 2855: 2854: 2845: 2843: 2772: 2702: 2698: 2692: 2673: 2669: 2665: 2661: 2657: 2653: 2649: 2644: 2640: 2636: 2631: 2563: 2559: 2555: 2551: 2547: 2542: 2537: 2480: 2476: 2472: 2468: 2464: 2459: 2454: 2448: 2444: 2436: 2423:lambda-term 2396:Lambda terms 2389: 2383: 2378: 2297: 2173: 2169: 2165: 2161: 1977: 1973: 1924: 1920: 1915: 1911: 1906: 1902: 1897: 1893: 1889: 1885: 1878:vector space 1875: 1870: 1862: 1858: 1849:only if the 1845: 1841: 1834: 1829: 1825: 1818: 1814: 1811: 1807: 1803: 1801: 1792:Sorted terms 1766: 1762: 1758: 1754: 1750: 1702: 1699:subject term 1698: 1695:pattern term 1694: 1690: 1686: 1682: 1678: 1672: 1667: 1663: 1658: 1654: 1650: 1646: 1643: 1635: 1627: 1623: 1543: 1467: 1462: 1458: 1454: 1453:), in which 1450: 1446: 1442: 1437: 1432: 1426: 1422: 1415: 1411: 1406: 1402: 1398: 1394: 1379: 1375: 1369: 1364: 1359: 1355: 1351: 1344: 1340: 1179: 1175: 1149: 1145: 1142:real numbers 1103: 1098: 1094: 1090: 1086: 1082: 1078: 1073: 1069: 1068:Given a set 1067: 1056: 1052: 1048: 1044: 950: 938: 933: 927: 923: 919: 912: 910: 906:term algebra 902: 898:term algebra 893: 887: 878: 874: 870: 866: 862: 856: 852: 848: 844: 842: 832: 828: 824: 820: 816: 812: 808: 804: 800: 796: 792: 788: 784: 780: 776: 772: 764: 760: 756: 755:, of a term 752: 748: 747:is called a 744: 742: 737: 725: 721: 717: 713: 710:structurally 709: 707: 651: 647: 639: 635: 625: 623: 609: 605: 601: 597: 593: 589: 585: 578: 574: 570: 566: 562: 554: 550: 546: 542: 538: 532: 524: 513: 506: 502: 498: 493: 489: 483: 476: 472: 465: 461: 457: 453: 449: 440: 433: 429: 422: 418: 413: 409: 405: 401: 400:, and every 396: 392: 385: 381: 374: 370: 363: 359: 347: 343: 339: 334: 330: 326: 322: 321:Given a set 320: 314: 310: 306: 302: 298: 273: 56: 35: 29: 5345:Type theory 5293:undecidable 5225:Truth value 5112:equivalence 4791:non-logical 4404:Enumeration 4394:Isomorphism 4341:cardinality 4325:Von Neumann 4290:Ultrafilter 4255:Uncountable 4189:equivalence 4106:Quantifiers 4096:Fixed-point 4065:First-order 3945:Consistency 3930:Proposition 3907:Traditional 3878:Lindström's 3868:Compactness 3810:Type theory 3755:Cardinality 3445:to itself. 3375:when given 2684:Lambda term 2421:Written as 2178:, the term 1863:well-sorted 1812:sorted term 1420:. The term 1358:, a unique 1116:quantifiers 1055:, using an 863:linear term 858:ground term 443:grammatical 380:from every 309:+1))/2 and 274:Besides in 93:, given an 59:first-order 48:noun phrase 5460:Categories 5156:elementary 4849:arithmetic 4717:Quantifier 4695:functional 4567:Expression 4285:Transitive 4229:identities 4214:complement 4147:hereditary 4130:Set theory 3678:3540058192 3642:C.C. Chang 3600:References 3268:April 2021 3240:Definition 2689:Motivation 2379:overloaded 1871:ill-sorted 1701:, and the 1397:in a term 1354:of a term 612:+1, using 452: ::= 38:denotes a 5427:Supertask 5330:Recursion 5288:decidable 5122:saturated 5100:of models 5023:deductive 5018:axiomatic 4938:Hilbert's 4925:Euclidean 4906:canonical 4829:axiomatic 4761:Signature 4690:Predicate 4579:Extension 4501:Ackermann 4426:Operation 4305:Universal 4295:Recursive 4270:Singleton 4265:Inhabited 4250:Countable 4240:Types of 4224:power set 4194:partition 4111:Predicate 4057:Predicate 3972:Syllogism 3962:Soundness 3935:Inference 3925:Tautology 3827:paradoxes 3687:1431-4657 2816:⋅ 2807:⁡ 2790:∫ 2786:⋅ 2746:⋅ 2737:⁡ 2720:∫ 2716:⋅ 2605:⋅ 2596:⁡ 2579:∫ 2496:∑ 2418:variables 2413:variables 2406:Notation 2360:→ 2354:× 2345:∗ 2320:→ 2311:∗ 2275:→ 2249:⟩ 2243:∗ 2237:→ 2222:∗ 2213:→ 2198:→ 2186:⟨ 2137:∈ 2131:→ 2116:→ 2085:→ 2079:× 2070:⟩ 2058:⟨ 2031:→ 2025:× 2016:∗ 2007:→ 2001:× 1948:∈ 1942:→ 1727:∗ 1718:∗ 1590:∗ 1581:∗ 1562:∗ 1520:∗ 1511:∗ 1488:∗ 1395:replacing 1388:reflexive 1315:∗ 1306:∗ 1272:∗ 1263:∗ 1237:∗ 1216:∗ 1020:θ 1016:⋅ 1001:∞ 986:∑ 967:θ 890:signature 767:for some 714:literally 486:signature 267:value of 246:≥ 228:∗ 189:∗ 122:∗ 67:variables 5412:Logicism 5405:timeline 5381:Concrete 5240:Validity 5210:T-schema 5203:Kripke's 5198:Tarski's 5193:semantic 5183:Strength 5132:submodel 5127:spectrum 5095:function 4943:Tarski's 4932:Elements 4919:geometry 4875:Robinson 4796:variable 4781:function 4754:spectrum 4744:Sentence 4700:variable 4643:Language 4596:Relation 4557:Automata 4547:Alphabet 4531:language 4385:-jection 4363:codomain 4349:Function 4310:Universe 4280:Infinite 4184:Relation 3967:Validity 3957:Argument 3855:theorem, 3667:(1973). 3648:(1977). 3613:(1999). 3455:Equation 3449:See also 3186:"%d 3126:#include 2915:sequence 2650:integral 1772:subject. 1765:+1, z ↦ 1626:(called 1459:embedded 1341:position 1108:formulas 888:Given a 749:renaming 656:", and " 61:term is 52:sentence 42:while a 5354:Related 5151:Diagram 5049: ( 5028:Hilbert 5013:Systems 5008:Theorem 4886:of the 4831:systems 4611:Formula 4606:Grammar 4522: ( 4466:General 4179:Forcing 4164:Element 4084:Monadic 3859:paradox 3800:Theorem 3736:General 3507:on the 3494:below). 2408:example 2375:⁠ 2337:⁠ 2100:⁠ 2050:⁠ 2046:⁠ 1984:⁠ 1745:⁠ 1707:⁠ 1649:a term 1647:matches 1642:A term 1445:, or a 1443:context 1360:subterm 1333:⁠ 1295:⁠ 904:initial 753:variant 751:, or a 654:+1)))/2 604:, 1) ∈ 471:, ..., 428:, ..., 261:⁠ 205:⁠ 201:⁠ 181:⁠ 177:⁠ 157:⁠ 149:⁠ 99:⁠ 44:formula 5117:finite 4880:Skolem 4833:  4808:Theory 4776:Symbol 4766:String 4749:atomic 4626:ground 4621:closed 4616:atomic 4572:ground 4535:syntax 4431:binary 4358:domain 4275:Finite 4040:finite 3898:Logics 3857:  3805:Theory 3685:  3675:  3621:  3579:below. 3490:, cf. 3225:return 3216:square 3192:" 3180:printf 3105:return 3087:square 3072:return 2944:form. 2942:prefix 2875:square 2411:Bound 2048:, and 1697:, the 1631:green. 1628:height 803:or as 642:+1))/2 592:, 1 ∈ 559:tuples 384:terms 317:+1)/2) 282:, and 5107:Model 4855:Peano 4712:Proof 4552:Arity 4481:Naive 4368:image 4300:Fuzzy 4260:Empty 4209:union 4154:Class 3795:Model 3785:Lemma 3743:Axiom 3466:Notes 3358:power 3171:& 3159:scanf 3036:<= 2938:infix 2703:bound 2701:, or 2699:local 2695:above 2566:,2)) 2560:power 2465:limit 2416:Free 1882:field 1840:,..., 1824:,..., 1769:+2 } 1624:depth 1382:is a 1343:, or 1178:+1)⋅( 716:, or 644:", " 553:maps 391:,..., 276:logic 87:false 5230:Type 5033:list 4837:list 4814:list 4803:Term 4737:rank 4631:open 4525:list 4337:Maps 4242:sets 4101:Free 4071:list 3821:list 3748:list 3683:ISSN 3673:ISBN 3619:ISBN 3484:bool 3328:and 3141:void 3135:main 2925:/2, 2921:/1, 2909:/2, 2905:/1, 2773:free 2384:See 2159:and 1972:0 ∈ 1970:and 1919:and 1901:and 1888:and 1808:type 1804:sort 1666:σ = 1636:size 1634:The 1345:path 1114:and 895:free 849:vars 630:tree 484:The 179:and 83:true 69:and 36:term 34:, a 4917:of 4899:of 4847:of 4379:Sur 4353:Map 4160:Ur- 4142:Set 3488:int 3354:div 3321:if 3298:if 3263:. 3219:)); 3198:sum 3150:int 3132:int 3093:int 3084:int 3075:res 3060:fct 3054:res 3039:upb 3027:lwb 3018:int 3012:for 3000:res 2997:int 2985:int 2979:fct 2976:int 2970:upb 2967:int 2961:lwb 2958:int 2952:sum 2949:int 2931:lim 2868:lim 2846:lim 2804:sin 2734:sin 2676:)) 2666:sin 2593:sin 2550:(1, 2548:sum 2483:)) 2473:div 2432:lim 1681:in 1174:⇒ ( 1144:, ∀ 1077:of 598:add 575:add 503:cos 499:sin 350:is 338:of 313:⋅(( 89:in 85:or 30:In 5462:: 5303:NP 4927:: 4921:: 4851:: 4528:), 4383:Bi 4375:In 3681:. 3644:; 3609:; 3559:: 3535:: 3430:.( 3356:, 3189:\n 3177:); 3069:); 3057:+= 3045:++ 2988:)) 2893:. 2881:. 2664:. 2660:,λ 2643:, 2639:, 2558:. 2554:,λ 2471:. 2467:(λ 2439:→∞ 2381:. 2168:∈ 1873:. 1761:↦ 1757:, 1753:↦ 1749:{ 1689:, 1546:+1 1471:12 1152:∈ 1148:: 949:= 908:. 885:. 877:⋅( 869:⋅( 765:tσ 763:= 722:un 712:, 650:⋅( 646:(( 638:⋅( 588:∈ 577:∈ 565:∈ 519:. 505:∈ 501:, 480:). 460:| 456:| 408:∈ 373:⊆ 362:⊆ 305:⋅( 286:. 271:. 57:A 5383:/ 5298:P 5053:) 4839:) 4835:( 4732:∀ 4727:! 4722:∃ 4683:= 4678:↔ 4673:→ 4668:∧ 4663:∨ 4658:¬ 4381:/ 4377:/ 4351:/ 4162:) 4158:( 4045:∞ 4035:3 3823:) 3721:e 3714:t 3707:v 3689:. 3627:. 3573:a 3571:+ 3569:b 3567:= 3565:b 3563:+ 3561:a 3557:b 3555:, 3553:a 3549:x 3547:+ 3545:y 3543:= 3541:y 3539:+ 3537:x 3533:y 3531:, 3529:x 3525:x 3523:+ 3521:y 3519:= 3517:y 3515:+ 3513:x 3443:x 3439:x 3435:x 3432:x 3428:x 3424:y 3420:y 3418:. 3416:x 3412:x 3410:. 3408:x 3404:2 3401:t 3397:1 3394:t 3390:2 3387:t 3384:1 3381:t 3377:x 3373:t 3369:t 3367:. 3365:x 3346:2 3343:t 3340:1 3337:t 3333:2 3330:t 3326:1 3323:t 3316:t 3314:. 3312:x 3308:t 3304:V 3302:∈ 3300:x 3293:V 3291:∈ 3289:x 3281:V 3270:) 3266:( 3234:} 3231:; 3228:0 3213:, 3210:n 3207:, 3204:1 3201:( 3195:, 3183:( 3174:n 3168:, 3162:( 3156:; 3153:n 3147:{ 3144:) 3138:( 3120:} 3117:; 3114:i 3111:* 3108:i 3102:{ 3099:) 3096:i 3090:( 3081:} 3078:; 3066:i 3063:( 3051:) 3048:i 3042:; 3033:i 3030:; 3024:= 3021:i 3015:( 3009:; 3006:0 3003:= 2991:{ 2982:( 2973:, 2964:, 2955:( 2927:x 2923:x 2919:x 2917:( 2911:x 2907:x 2903:x 2899:n 2897:/ 2895:x 2891:n 2883:i 2879:i 2850:C 2829:t 2826:d 2822:) 2819:t 2813:k 2810:( 2799:b 2794:a 2783:k 2759:t 2756:d 2752:) 2749:t 2743:k 2740:( 2729:b 2724:a 2713:t 2674:t 2672:⋅ 2670:k 2668:( 2662:t 2658:b 2656:, 2654:a 2652:( 2645:k 2641:b 2637:a 2632:t 2617:t 2614:d 2611:) 2608:t 2602:k 2599:( 2588:b 2583:a 2564:i 2562:( 2556:i 2552:n 2543:n 2538:i 2521:2 2517:i 2511:n 2506:1 2503:= 2500:i 2481:n 2479:, 2477:x 2475:( 2469:n 2460:x 2455:n 2449:n 2447:/ 2445:x 2437:n 2363:W 2357:W 2351:N 2348:: 2317:v 2308:a 2298:N 2284:a 2281:+ 2272:v 2246:b 2234:w 2228:, 2225:a 2219:) 2210:0 2204:+ 2195:v 2189:( 2174:N 2170:V 2166:b 2164:, 2162:a 2145:W 2141:V 2128:w 2122:, 2113:v 2088:N 2082:W 2076:W 2073:: 2067:. 2064:, 2061:. 2034:W 2028:N 2022:W 2019:: 2013:, 2010:W 2004:W 1998:W 1995:: 1992:+ 1978:N 1974:C 1956:W 1952:C 1939:0 1925:N 1921:C 1916:W 1912:C 1907:N 1903:V 1898:W 1894:V 1890:N 1886:W 1859:f 1855:i 1851:i 1846:n 1842:t 1838:1 1835:t 1830:n 1826:t 1822:1 1819:t 1817:( 1815:f 1767:a 1763:a 1759:y 1755:a 1751:x 1733:) 1730:z 1724:y 1721:( 1715:x 1691:t 1687:u 1683:t 1679:p 1673:p 1670:| 1668:t 1664:u 1659:t 1655:u 1651:t 1644:u 1596:) 1593:3 1587:2 1584:( 1578:1 1573:) 1569:. 1565:( 1559:a 1544:b 1526:) 1523:3 1517:2 1514:( 1508:1 1503:) 1500:1 1497:+ 1494:b 1491:( 1485:a 1468:t 1463:t 1455:u 1451:p 1438:t 1433:u 1427:p 1423:t 1416:p 1412:t 1407:u 1403:p 1399:t 1376:a 1370:p 1367:| 1365:t 1356:t 1352:p 1321:) 1318:z 1312:y 1309:( 1303:x 1278:) 1275:3 1269:2 1266:( 1260:1 1255:) 1252:) 1249:2 1246:+ 1243:a 1240:( 1234:) 1231:1 1228:+ 1225:a 1222:( 1219:( 1213:a 1180:x 1176:x 1161:R 1150:x 1146:x 1127:R 1104:n 1099:n 1095:R 1091:n 1087:n 1083:n 1079:n 1074:n 1070:R 1057:i 1053:h 1049:i 1045:h 1029:i 1024:h 1011:i 1007:f 996:0 993:= 990:i 982:= 977:1 974:+ 971:h 954:0 951:f 947:0 945:θ 939:h 934:h 928:i 924:f 920:i 916:0 913:f 879:n 875:n 871:n 867:x 853:t 851:( 845:t 833:a 831:+ 829:b 827:= 825:y 823:+ 821:x 817:a 815:+ 813:b 811:= 809:b 807:+ 805:a 801:x 799:+ 797:y 795:= 793:y 791:+ 789:x 781:t 777:t 773:u 761:u 757:u 745:t 738:n 686:2 682:) 679:1 676:+ 673:n 670:( 667:n 652:n 648:n 640:n 636:n 634:( 610:n 606:T 602:n 600:( 594:T 590:T 586:n 582:2 579:F 571:C 567:V 563:n 557:- 555:n 551:f 547:n 543:x 539:c 528:0 525:F 517:2 514:F 510:1 507:F 494:n 490:F 477:n 473:t 469:1 466:t 464:( 462:f 458:c 454:x 450:t 434:n 430:t 426:1 423:t 421:( 419:f 414:n 410:F 406:f 402:n 397:n 393:t 389:1 386:t 382:n 377:, 375:T 371:C 366:, 364:T 360:V 348:T 344:n 340:n 335:n 331:F 327:C 323:V 315:n 311:n 307:n 303:n 269:x 249:0 243:) 240:1 237:+ 234:x 231:( 225:) 222:1 219:+ 216:x 213:( 165:+ 153:x 137:) 134:1 131:+ 128:x 125:( 119:) 116:1 113:+ 110:x 107:( 20:)

Index

Variant (logic)
mathematical logic
mathematical object
formula
noun phrase
sentence
first-order
recursively constructed
variables
function symbols
predicate symbol
atomic formula
true
false
bivalent logics
interpretation
real-numbered
logic
universal algebra
rewriting systems

recursively defined
grammatical
signature
Ternary operations
domain of discourse
tuples
infix notation
tree
rational arithmetic

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