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Original proof of Gödel's completeness theorem

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17: 5224: 1639:. This formula is indeed equivalent to φ because it states that for every x, if there is a y that satisfies Q'(x,y), then (something) holds, and furthermore, we know that there is such a y, because for every x', there is a y' that satisfies Q'(x',y'). Therefore φ follows from this formula. It is also easy to show that if the formula is false, then so is φ. 1186: 5645: 3606: 4863: 2723:
is a string of quantifiers containing all quantifiers in (S) and (S') interleaved among themselves in any fashion, but maintaining the relative order inside (S) and (S'), will be equivalent to the original formula Φ'(this is yet another basic result in first-order predicate calculus that we rely on).
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in his doctoral dissertation of 1929 (and a shorter version of the proof, published as an article in 1930, titled "The completeness of the axioms of the functional calculus of logic" (in German)) is not easy to read today; it uses concepts and formalisms that are no longer used and terminology that
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This is yet another basic result of first-order predicate calculus. Depending on the particular formalism adopted for the calculus, it may be seen as a simple application of a "functional substitution" rule of inference, as in Gödel's paper, or it may be proved by considering the formal proof of
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This is the most basic form of the completeness theorem. We immediately restate it in a form more convenient for our purposes: When we say "all structures", it is important to specify that the structures involved are classical (Tarskian) interpretations I, where I = <U,F> (U is a
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There are standard techniques for rewriting an arbitrary formula into one that does not use function or constant symbols, at the cost of introducing additional quantifiers; we will therefore assume that all formulas are free of such symbols. Gödel's paper uses a version of first-order predicate
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by successively restricting the class of all formulas φ for which we need to prove "φ is either refutable or satisfiable". At the beginning we need to prove this for all possible formulas φ in our language. However, suppose that for every formula φ there is some formula ψ taken from a more
931: 5363: 5219:{\displaystyle D_{n}\Leftarrow D_{n-1}\wedge (\forall z_{1}\ldots z_{(n-1)m+1})(\exists z_{(n-1)m+2}\ldots z_{nm+1})B_{n}\Leftarrow D_{n-1}\wedge (\forall z_{a_{1}^{n}}\ldots z_{a_{k}^{n}})(\exists y_{1}\ldots y_{m})\varphi (z_{a_{1}^{n}}\ldots z_{a_{k}^{n}},y_{1}\ldots y_{m})} 417:, such that "ψ is either refutable or satisfiable" → "φ is either refutable or satisfiable". Then, once this claim (expressed in the previous sentence) is proved, it will suffice to prove "φ is either refutable or satisfiable" only for φ's belonging to the class 7971:
Gödel also considered the case where there are a countably infinite collection of formulas. Using the same reductions as above, he was able to consider only those cases where each formula is of degree 1 and contains no uses of equality. For a countable collection of formulas
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We fix some axiomatization (i.e. a syntax-based, machine-manageable proof system) of the predicate calculus: logical axioms and rules of inference. Any of the several well-known equivalent axiomatizations will do. Gödel's original proof assumed the
3168:, replacing in it all occurrences of Q by some other formula with the same free variables, and noting that all logical axioms in the formal proof remain logical axioms after the substitution, and all rules of inference still apply in the same way. 4666: 6656: 4805: 82:), i.e. there are no special axioms expressing the properties of (object) equality as a special relation symbol. After the basic form of the theorem has been proved, it will be easy to extend it to the case of predicate calculus 3034: 4161: 4259: 1738: 1381: 1181:{\displaystyle \varphi =(\forall x_{1}\cdots \forall x_{k_{1}})(\exists x_{k_{1}+1}\cdots \exists x_{k_{2}})\cdots (\forall x_{k_{n-2}+1}\cdots \forall x_{k_{n-1}})(\exists x_{k_{n-1}+1}\cdots \exists x_{k_{n}})(\Phi )} 8148: 653: 5640:{\displaystyle D_{1}\equiv (\exists z_{1}\ldots z_{m+1})\varphi (z_{a_{1}^{1}}\ldots z_{a_{k}^{1}},z_{2},z_{3}\ldots z_{m+1})\equiv (\exists z_{1}\ldots z_{m+1})\varphi (z_{1}\ldots z_{1},z_{2},z_{3}\ldots z_{m+1})} 3785: 3284: 7030:
Gödel reduced a formula containing instances of the equality predicate to ones without it in an extended language. His method involves replacing a formula φ containing some instances of equality with the formula
49:. Our languages allow constant, function and relation symbols. Structures consist of (non-empty) domains and interpretations of the relevant symbols as constant members, functions or relations over that domain. 7959:. If this new formula is refutable, the original φ was as well; the same is true of satisfiability, since we may take a quotient of satisfying model of the new formula by the equivalence relation representing 5319: 576: 1920: 7848: 7578: 2419: 2730: 1999: 4063: 816: 7190: 1463: 881: 3601:{\displaystyle \neg ((\forall x')(\exists y')(\forall u)(\exists v)(P)\psi (x,y\mid x',y')\wedge (\forall x)(\forall y)((\forall u)(\exists v)(P)\psi \rightarrow (\forall u)(\exists v)(P)\psi ))} 2651: 2267: 6503: 917:
Our generic formula φ now is a sentence, in normal form, and its prefix starts with a universal quantifier and ends with an existential quantifier. Let us call the class of all such formulas
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is either refutable (its negation is always true) or satisfiable, i.e. there is some model in which it holds (it might even be always true, i.e. a tautology); this model is simply assigning
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is often obscure. The version given below attempts to represent all the steps in the proof and all the important ideas faithfully, while restating the proof in the modern language of
2934: 7314: 7605: 6440: 4305: 1960: 7898: 4357: 5355: 907: 3688: 7997: 4508: 1861: 3362: 3194: 3166: 3140: 3117: 8029: 7953: 7927: 3054: 1809: 1765: 1430: 1410: 1257: 1233: 1213: 7869: 7335: 6113: 3649: 3629: 3286:. Here (x,y | x',y') means that instead of ψ we are writing a different formula, in which x and y are replaced with x' and y'. Q(x,y) is simply replaced by 8056: 6683: 6530: 6394: 6370: 6340: 6309: 6282: 6251: 6224: 6197: 6170: 6140: 6080: 6049: 6022: 5995: 5968: 5941: 5914: 5887: 5860: 5826: 5799: 5772: 5745: 5710: 5679: 4693: 4503: 3805: 3094: 3074: 2981: 2957: 1789: 6538: 4701: 396:
holds and φ is valid in all structures, then ¬φ is not satisfiable in any structure and therefore refutable; then ¬¬φ is provable and then so is φ, thus
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of degree 1. φ cannot be of degree 0, since formulas in R have no free variables and don't use constant symbols. So the formula φ has the general form:
4068: 2990: 4166: 1660: 1303: 5943:; we will inductively define a general assignment to them by a sort of "majority vote": Since there are infinitely many assignments (one for each 8061: 597: 213:. While we cannot do this by simply rearranging the quantifiers, we show that it is yet enough to prove the theorem for sentences of that form. 8244: 5229: 2413:
And since these two formulas are equivalent, if we replace the first with the second inside Φ, we obtain the formula Φ' such that Φ≡Φ':
2589:{\displaystyle \Phi '=(\forall x')(\exists y')Q(x',y')\wedge (\forall x)(\forall y)(\forall u)(\exists v)(P)(Q(x,y)\rightarrow \psi )} 356:
non-empty (possibly infinite) set of objects, whereas F is a set of functions from expressions of the interpreted symbolism into U).
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The same material as the dissertation, except with briefer proofs, more succinct explanations, and omitting the lengthy introduction.
2895:{\displaystyle \Psi =(\forall x')(\forall x)(\forall y)(\forall u)(\exists y')(\exists v)(P)Q(x',y')\wedge (Q(x,y)\rightarrow \psi )} 2164:{\displaystyle \Phi =(\forall x')(\exists y')Q(x',y')\wedge (\forall x)(\forall y)(Q(x,y)\rightarrow (\forall u)(\exists v)(P)\psi )} 526: 388:
holds, and φ is not satisfiable in any structure, then ¬φ is valid in all structures and therefore provable, thus φ is refutable and
25: 1866: 686:, which is in normal form) begin with a universal quantifier and end with an existential quantifier. To achieve this for a generic 7611: 7341: 3700: 3199: 1436: − 1). φ states that for every x there is a y such that... (something). It would have been nice to have a predicate 1643:, in general there is no such predicate Q'. However, this idea can be understood as a basis for the following proof of the Lemma. 1632:{\displaystyle (\forall x')(\forall x)(\forall y)(\forall u)(\exists v)(\exists y')(P)Q'(x',y')\wedge (Q'(x,y)\rightarrow \psi )} 3990: 1236: 8299: 3690:
is provable, and φ is refutable. We have proved that φ is either satisfiable or refutable, and this concludes the proof of the
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to be the number of universal quantifier blocks, separated by existential quantifier blocks as shown above, in the prefix of
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true, we construct an interpretation of the language's predicates that makes φ true. The universe of the model will be the
2403:{\displaystyle (Q(x,y)\rightarrow (\forall u)(\exists v)(P)\psi )\equiv (\forall u)(\exists v)(P)(Q(x,y)\rightarrow \psi )} 7963:. This quotient is well-defined with respect to the other predicates, and therefore will satisfy the original formula φ. 925:
is either refutable or satisfiable. Given our formula φ, we group strings of quantifiers of one kind together in blocks:
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will be true when each proposition is evaluated in this fashion. This follows from the completeness of the underlying
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their respective arities), and φ' is the formula φ with all occurrences of equality replaced with the new predicate
4366: 3965:{\displaystyle (\forall x_{1}\ldots x_{k})(\exists y_{1}\ldots y_{m})\varphi (x_{1}\ldots x_{k},y_{1}\ldots y_{m}).} 3289: 121:. This is possible because for every sentence, there is an equivalent one in prenex form whose first quantifier is 4422: 4820: 3811:
in that case. This is why we cannot naively use the argument appearing at the comment that precedes the proof.
2602: 2206: 2177: 5226:, where the latter implication holds by variable substitution, since the ordering of the tuples is such that 2676: 8304: 7194: 7584: 6024:
true, or infinitely many make it false and only finitely many make it true. In the former case, we choose
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is either true in the general assignment, or not assigned by it (because it never appears in any of the
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We assume without proof all the basic well-known results about our formalism that we need, such as the
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the formulas, and prove the uncountable case with the same argument as the countable one, except with
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to be true in general; in the latter we take it to be false in general. Then from the infinitely many
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by some other formula dependent on the same variables, and we will still get a provable formula. (
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are assigned the same truth value as in the general assignment, we pick a general assignment to
3344: 3176: 3148: 3122: 3099: 2261:, the following equivalence is easily provable with the help of whatever formalism we're using: 433:) is provable), then it is indeed the case that "ψ is either refutable or satisfiable" → " 8002: 7932: 7906: 3039: 1794: 1750: 1415: 1386: 1242: 1218: 1198: 438: 68: 7854: 7320: 6085: 3634: 3614: 1985:
be a previously unused relation symbol that takes as many arguments as the sum of lengths of
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is the required one to make (something) true. Then we could have written a formula of degree
8252: 8217: 8209: 6651:{\displaystyle (\exists y_{1}\ldots y_{m})\varphi (a_{1}^{n}\ldots a_{k}^{n},y_{1}...y_{m})} 4800:{\displaystyle (\exists z_{1}\ldots z_{nm+1})(B_{1}\wedge B_{2}\wedge \cdots \wedge B_{n}).} 94:
In the following, we state two equivalent forms of the theorem, and show their equivalence.
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range over all possible k-tuples of natural numbers. So φ is satisfiable, and we are done.
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to the subpropositions from which B is built. The reason for that is the completeness of
690:(subject to restrictions we have already proved), we take some one-place relation symbol 6658:
is true by construction. But this implies that φ itself is true in the model, since the
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Theorem 2. Every formula φ is either refutable or satisfiable in some structure.
29: 5774:; "distinct" here means either distinct predicates, or distinct bound variables) in 117:) at the beginning. Furthermore, we reduce it to formulas whose first quantifier is 4419:
denotes the sum of the terms of the tuple.] Denote the nth tuple in this order by
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is provable. Now we can replace all occurrences of Q inside the provable formula
4156:{\displaystyle \Sigma _{k}(x_{1}\ldots x_{k})<\Sigma _{k}(y_{1}\ldots y_{k})} 453: 297: 102: 8163: 3029:{\displaystyle \Psi \equiv \Phi '\equiv \Phi \wedge \Phi \rightarrow \varphi } 4254:{\displaystyle \Sigma _{k}(x_{1}\ldots x_{k})=\Sigma _{k}(y_{1}\ldots y_{k})} 1733:{\displaystyle \varphi =(\forall x)(\exists y)(\forall u)(\exists v)(P)\psi } 1376:{\displaystyle \varphi =(\forall x)(\exists y)(\forall u)(\exists v)(P)\psi } 8248: 5720:
there is some way of assigning truth values to the distinct subpropositions
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We assume classical logic (as opposed to intuitionistic logic for example).
8143:{\displaystyle B_{1}^{1}\ldots B_{k}^{1},\ldots ,B_{1}^{k}\ldots B_{k}^{k}} 8200:(1930). "Die Vollständigkeit der Axiome des logischen Funktionenkalküls". 6257:. But this contradicts the fact that for the finite collection of general 3611:
and this formula is provable; since the part under negation and after the
328:, or all of them are not refutable and therefore each holds in some model. 8162:(or at least some weak form of it) is needed. Using the full AC, one can 648:{\displaystyle \neg \psi =\forall x_{1}\cdots \forall x_{n}\neg \varphi } 37:. This outline should not be considered a rigorous proof of the theorem. 340:
hold (in case all are not refutable) in order to build a model in which
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sign is obviously provable, and the part under negation and before the
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Finally, we would like, for reasons of technical convenience, that the
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Reducing the theorem to sentences (formulas with no free variables) in
1235:. The following lemma, which Gödel adapted from Skolem's proof of the 307:
We extend this result to more and more complex and lengthy sentences,
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We will now show that there is such an assignment of truth values to
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Theorem 1. Every valid formula (true in all structures) is provable.
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When there is an uncountably infinite collection of formulas, the
5685:, it follows that φ is refutable. On the other hand, suppose that 5314:{\displaystyle (\forall k)(a_{1}^{n}\ldots a_{k}^{n})<(n-1)m+2} 3980: 452:(which no longer uses function or constant symbols) and apply the 97:
Later, we prove the theorem. This is done in the following steps:
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calculus that has no function or constant symbols to begin with.
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and therefore by assumption either refutable or satisfiable. If
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are some quantifier strings, ρ and ρ' are quantifier-free, and,
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is either refutable or satisfiable, then so is every formula in
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be tuples of previously unused variables of the same length as
1239:, lets us sharply reduce the complexity of the generic formula 571:{\displaystyle \psi =\exists x_{1}\cdots \exists x_{n}\varphi } 1915:{\displaystyle \forall x_{1}\forall x_{2}\cdots \forall x_{n}} 324:, so that either any of them is refutable and therefore so is 7843:{\displaystyle (\forall x_{1}\ldots x_{m},y_{1}\ldots x_{m})} 7573:{\displaystyle (\forall x_{1}\ldots x_{k},y_{1}\ldots x_{k})} 3780:{\displaystyle (\forall u)(\exists v)(P)\psi (x,y\mid x',y')} 3279:{\displaystyle (\forall u)(\exists v)(P)\psi (x,y\mid x',y')} 2673:
occurs in ρ. Under such conditions every formula of the form
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above, we only need to prove our theorem for formulas φ in
8150:. The remainder of the proof then went through as before. 4058:{\displaystyle (x_{1}\ldots x_{k})<(y_{1}\ldots y_{k})} 7026:
Extension to first-order predicate calculus with equality
811:{\displaystyle \psi =\forall y(P)\exists z(\Phi \wedge )} 216:
Finally we prove the theorem for sentences of that form.
7185:{\displaystyle (\forall x)Eq(x,x)\wedge (\forall x,y,z)} 682:(that is, the string of quantifiers at the beginning of 484:, if there are any, are found at the very beginning of 6145:
This general assignment must lead to every one of the
876:{\displaystyle \forall y\exists z(F(y)\vee \neg F(z))} 8064: 8037: 8005: 7978: 7935: 7909: 7878: 7857: 7614: 7587: 7344: 7323: 7197: 7040: 6664: 6541: 6511: 6448: 6402: 6382: 6351: 6345:
From this general assignment, which makes all of the
6321: 6290: 6263: 6232: 6205: 6178: 6151: 6121: 6088: 6061: 6030: 6003: 5976: 5949: 5922: 5895: 5868: 5841: 5807: 5780: 5753: 5726: 5691: 5660: 5366: 5327: 5232: 4866: 4823: 4704: 4674: 4511: 4484: 4425: 4369: 4313: 4267: 4169: 4071: 3993: 3836: 3793: 3703: 3673: 3637: 3617: 3373: 3347: 3292: 3202: 3179: 3151: 3125: 3102: 3082: 3062: 3042: 2993: 2969: 2945: 2911: 2733: 2679: 2605: 2422: 2270: 2209: 2180: 2002: 1928: 1869: 1840: 1797: 1777: 1753: 1663: 1466: 1418: 1389: 1306: 1245: 1221: 1201: 934: 889: 824: 732: 600: 529: 219:
This is done by first noting that a sentence such as
304:, with the existential quantifiers playing no role. 8142: 8050: 8023: 7991: 7947: 7921: 7892: 7863: 7842: 7599: 7572: 7329: 7308: 7184: 6999:) satisfied. By taking a submodel with only these 6677: 6650: 6524: 6497: 6434: 6388: 6364: 6334: 6303: 6276: 6245: 6218: 6191: 6164: 6134: 6107: 6074: 6043: 6016: 5989: 5962: 5935: 5908: 5881: 5854: 5820: 5793: 5766: 5739: 5704: 5673: 5639: 5349: 5313: 5218: 4842: 4799: 4687: 4660: 4497: 4467: 4411: 4351: 4299: 4253: 4155: 4057: 3964: 3799: 3779: 3682: 3643: 3623: 3600: 3356: 3331: 3278: 3188: 3160: 3134: 3111: 3088: 3068: 3048: 3028: 2975: 2951: 2928: 2894: 2711: 2645: 2588: 2402: 2245: 2192: 2163: 1954: 1914: 1855: 1803: 1783: 1759: 1732: 1631: 1424: 1404: 1375: 1251: 1227: 1207: 1180: 921:. We are faced with proving that every formula in 901: 875: 810: 647: 570: 6498:{\displaystyle \Psi (z_{u_{1}}\ldots z_{u_{i}})} 3787:instead of Q(x',y') from the beginning, because 3173:In this particular case, we replace Q(x',y') in 8191:(Doctoral dissertation). University Of Vienna. 6812:has the property that the "last arguments" of 5647:is obviously a corollary of φ as well. So the 4412:{\displaystyle \Sigma _{k}(x_{1}\ldots x_{k})} 3332:{\displaystyle (\forall u)(\exists v)(P)\psi } 128:Reducing the theorem to sentences of the form 7013:... objects, we have a model satisfying  6882:of these appear as "first arguments" in some 671:, that is, a formula with no free variables. 8: 8193:The first proof of the completeness theorem. 6855:Therefore in a model that satisfies all the 6784:so that they appear as "first arguments" in 3815:Proving the theorem for formulas of degree 1 913:Reducing the theorem to formulas of degree 1 883:is clearly provable, it is easy to see that 503:by quantifying them existentially: if, say, 7929:denote the predicates appearing in φ (with 6738:s, which we may call "first arguments" and 4468:{\displaystyle (a_{1}^{n}\ldots a_{k}^{n})} 1831:of variables rather than single variables; 499:Next, we eliminate all free variables from 6819:appear, in every possible combinations of 663:is refutable. We see that we can restrict 488:). It follows now that we need only prove 8189:Über die Vollständigkeit des Logikkalküls 8134: 8129: 8116: 8111: 8092: 8087: 8074: 8069: 8063: 8042: 8036: 8015: 8010: 8004: 7983: 7977: 7934: 7908: 7877: 7856: 7825: 7812: 7790: 7777: 7749: 7736: 7705: 7692: 7664: 7651: 7638: 7625: 7613: 7586: 7555: 7542: 7520: 7507: 7479: 7466: 7435: 7422: 7394: 7381: 7368: 7355: 7343: 7322: 7196: 7039: 6669: 6663: 6639: 6620: 6607: 6602: 6589: 6584: 6565: 6552: 6540: 6516: 6510: 6484: 6479: 6464: 6459: 6447: 6423: 6410: 6401: 6381: 6356: 6350: 6326: 6320: 6295: 6289: 6268: 6262: 6237: 6231: 6226:were false under the general assignment, 6210: 6204: 6183: 6177: 6156: 6150: 6126: 6120: 6093: 6087: 6066: 6060: 6035: 6029: 6008: 6002: 5981: 5975: 5954: 5948: 5927: 5921: 5900: 5894: 5873: 5867: 5846: 5840: 5812: 5806: 5785: 5779: 5758: 5752: 5731: 5725: 5696: 5690: 5665: 5659: 5622: 5609: 5596: 5583: 5570: 5545: 5532: 5504: 5491: 5478: 5463: 5458: 5453: 5438: 5433: 5428: 5403: 5390: 5371: 5365: 5332: 5326: 5275: 5270: 5257: 5252: 5231: 5207: 5194: 5179: 5174: 5169: 5154: 5149: 5144: 5125: 5112: 5091: 5086: 5081: 5066: 5061: 5056: 5031: 5018: 4996: 4962: 4922: 4909: 4884: 4871: 4865: 4843:{\displaystyle \varphi \rightarrow D_{n}} 4834: 4822: 4785: 4766: 4753: 4728: 4715: 4703: 4679: 4673: 4640: 4606: 4572: 4557: 4552: 4547: 4532: 4527: 4522: 4510: 4489: 4483: 4456: 4451: 4438: 4433: 4424: 4400: 4387: 4374: 4368: 4340: 4321: 4312: 4288: 4275: 4266: 4242: 4229: 4216: 4200: 4187: 4174: 4168: 4144: 4131: 4118: 4102: 4089: 4076: 4070: 4046: 4033: 4014: 4001: 3992: 3950: 3937: 3924: 3911: 3892: 3879: 3860: 3847: 3835: 3792: 3702: 3672: 3636: 3616: 3372: 3346: 3291: 3201: 3178: 3150: 3124: 3101: 3081: 3061: 3041: 2992: 2968: 2944: 2910: 2732: 2678: 2646:{\displaystyle (S)\rho \wedge (S')\rho '} 2604: 2421: 2269: 2246:{\displaystyle (\forall u)(\exists v)(P)} 2208: 2193:{\displaystyle \Phi \rightarrow \varphi } 2179: 2001: 1946: 1933: 1927: 1906: 1890: 1877: 1868: 1839: 1796: 1776: 1752: 1662: 1465: 1417: 1388: 1305: 1244: 1220: 1200: 1158: 1153: 1123: 1118: 1091: 1086: 1056: 1051: 1027: 1022: 998: 993: 972: 967: 951: 933: 888: 823: 731: 633: 617: 599: 559: 543: 528: 437:is either refutable or satisfiable" (the 6776:, and for every possible combination of 5321:. But the last formula is equivalent to 1654: + 1; then we can write it as 1460:, which is equivalent to φ, namely 722:(the remaining, quantifier-free part of 8154:Extension to arbitrary sets of formulas 7967:Extension to countable sets of formulas 6823:of them, as "first arguments" in other 2712:{\displaystyle (T)(\rho \wedge \rho ')} 331:We finally use the models in which the 7309:{\displaystyle \wedge (\forall x,y,z)} 6864:s, there are objects corresponding to 6752:for example. Its "last arguments" are 5747:(ordered by their first appearance in 90:Statement of the theorem and its proof 7600:{\displaystyle \wedge \cdots \wedge } 6742:s that we may call "last arguments". 6342:true matches the general assignment. 714:, where (P) stands for the prefix of 320: = 1,2...), built out from 7: 6535:In this model, each of the formulas 2203:Now since the string of quantifiers 1269: ≥ 1. If every formula in 421:. If φ is provably equivalent to ψ ( 8245:Stanford Encyclopedia of Philosophy 6435:{\displaystyle (u_{1}\ldots u_{i})} 4300:{\displaystyle (x_{1}\ldots x_{k})} 3697:Notice that we could not have used 448:Next we consider a generic formula 7618: 7348: 7204: 7080: 7044: 6545: 6449: 6383: 5916:appear in the same order in every 5525: 5383: 5236: 5105: 5049: 4955: 4902: 4708: 4371: 4213: 4171: 4115: 4073: 3872: 3840: 3794: 3719: 3707: 3674: 3571: 3559: 3532: 3520: 3505: 3493: 3429: 3417: 3400: 3383: 3374: 3351: 3348: 3308: 3296: 3218: 3206: 3183: 3180: 3155: 3152: 3129: 3126: 3106: 3103: 3096:, which is equivalent to it; thus 3083: 3063: 3017: 3011: 3001: 2994: 2970: 2946: 2929:{\displaystyle \Phi '\equiv \Psi } 2923: 2913: 2813: 2796: 2784: 2772: 2760: 2743: 2734: 2538: 2526: 2514: 2502: 2454: 2437: 2424: 2352: 2340: 2310: 2298: 2225: 2213: 2181: 2137: 2125: 2089: 2077: 2029: 2012: 2003: 1899: 1883: 1870: 1844: 1747:is the remainder of the prefix of 1709: 1697: 1685: 1673: 1535: 1523: 1511: 1499: 1487: 1470: 1352: 1340: 1328: 1316: 1259:we need to prove the theorem for: 1172: 1146: 1111: 1079: 1044: 1015: 986: 960: 944: 855: 831: 825: 787: 763: 754: 739: 639: 626: 610: 601: 552: 536: 480:means that all the quantifiers in 14: 6852:with the corresponding property. 6780:of these variables there is some 3975:Now we define an ordering of the 1955:{\displaystyle x_{1}\ldots x_{n}} 1791:is the quantifier-free matrix of 74:We axiomatize predicate calculus 6199:being true, since if one of the 2669:occurs in ρ' and no variable of 2253:does not contain variables from 6442:precisely when the proposition 6396:should be true of the naturals 4352:{\displaystyle (y_{1}...y_{k})} 3651:sign is obviously φ, just with 1452:) would be true if and only if 7837: 7834: 7831: 7805: 7796: 7770: 7764: 7761: 7758: 7755: 7729: 7711: 7685: 7676: 7673: 7670: 7615: 7567: 7564: 7561: 7535: 7526: 7500: 7494: 7491: 7488: 7485: 7459: 7441: 7415: 7406: 7403: 7400: 7345: 7303: 7300: 7297: 7285: 7276: 7273: 7261: 7252: 7249: 7246: 7234: 7225: 7222: 7201: 7179: 7176: 7173: 7161: 7152: 7149: 7137: 7128: 7125: 7122: 7110: 7101: 7098: 7077: 7071: 7059: 7050: 7041: 6645: 6577: 6571: 6542: 6492: 6452: 6429: 6403: 6253:would also be false for every 5997:, either infinitely many make 5634: 5563: 5557: 5522: 5516: 5421: 5415: 5380: 5350:{\displaystyle D_{n-1}\wedge } 5299: 5287: 5281: 5245: 5242: 5233: 5213: 5137: 5131: 5102: 5099: 5046: 5024: 5011: 4975: 4963: 4952: 4949: 4935: 4923: 4899: 4877: 4827: 4791: 4746: 4743: 4705: 4655: 4619: 4607: 4585: 4573: 4515: 4462: 4426: 4406: 4380: 4346: 4314: 4294: 4268: 4248: 4222: 4206: 4180: 4150: 4124: 4108: 4082: 4052: 4026: 4020: 3994: 3956: 3904: 3898: 3869: 3866: 3837: 3774: 3740: 3734: 3728: 3725: 3716: 3713: 3704: 3595: 3592: 3586: 3580: 3577: 3568: 3565: 3556: 3553: 3547: 3541: 3538: 3529: 3526: 3517: 3514: 3511: 3502: 3499: 3490: 3484: 3450: 3444: 3438: 3435: 3426: 3423: 3414: 3411: 3397: 3394: 3380: 3377: 3323: 3317: 3314: 3305: 3302: 3293: 3273: 3239: 3233: 3227: 3224: 3215: 3212: 3203: 3020: 2983:is satisfiable in a structure 2889: 2883: 2880: 2868: 2862: 2856: 2834: 2828: 2822: 2819: 2810: 2807: 2793: 2790: 2781: 2778: 2769: 2766: 2757: 2754: 2740: 2724:To wit, we form Ψ as follows: 2706: 2689: 2686: 2680: 2632: 2621: 2612: 2606: 2583: 2577: 2574: 2562: 2556: 2553: 2547: 2544: 2535: 2532: 2523: 2520: 2511: 2508: 2499: 2493: 2471: 2465: 2451: 2448: 2434: 2397: 2391: 2388: 2376: 2370: 2367: 2361: 2358: 2349: 2346: 2337: 2331: 2325: 2319: 2316: 2307: 2304: 2295: 2292: 2289: 2277: 2271: 2240: 2234: 2231: 2222: 2219: 2210: 2184: 2158: 2152: 2146: 2143: 2134: 2131: 2122: 2119: 2116: 2104: 2098: 2095: 2086: 2083: 2074: 2068: 2046: 2040: 2026: 2023: 2009: 1850: 1841: 1724: 1718: 1715: 1706: 1703: 1694: 1691: 1682: 1679: 1670: 1626: 1620: 1617: 1605: 1594: 1588: 1566: 1555: 1549: 1546: 1532: 1529: 1520: 1517: 1508: 1505: 1496: 1493: 1484: 1481: 1467: 1396: 1390: 1367: 1361: 1358: 1349: 1346: 1337: 1334: 1325: 1322: 1313: 1175: 1169: 1166: 1108: 1105: 1041: 1035: 983: 980: 941: 902:{\displaystyle \varphi =\psi } 870: 867: 861: 849: 843: 837: 805: 802: 799: 793: 781: 775: 769: 760: 751: 745: 582:is satisfiable in a structure 404:Proof of theorem 2: first step 78:(sometimes confusingly called 58:Hilbert-Ackermann proof system 47:first-order predicate calculus 1: 3683:{\displaystyle \neg \varphi } 1962:are some distinct variables. 1650:Let φ be a formula of degree 655:is provable, and then so is ¬ 413:restricted class of formulas 7992:{\displaystyle \varphi ^{i}} 6878:... and each combination of 6315:where the assignment making 6311:, there are infinitely many 392:holds. If on the other hand 380:Equivalence of both theorems 26:Gödel's completeness theorem 8172:Boolean prime ideal theorem 7999:of degree 1, we may define 3056:is satisfiable as well. If 1856:{\displaystyle (\forall x)} 1300: + 1 of the form 8321: 8202:Monatshefte für Mathematik 7893:{\displaystyle \varphi '.} 3357:{\displaystyle \neg \Phi } 3189:{\displaystyle \neg \Phi } 3161:{\displaystyle \neg \Phi } 3135:{\displaystyle \neg \Phi } 3112:{\displaystyle \neg \Phi } 1993:; we consider the formula 456:theorem to find a formula 8024:{\displaystyle B_{k}^{i}} 7948:{\displaystyle k\ldots m} 7922:{\displaystyle A\ldots Z} 6891:, meaning that for every 6284:assignments appearing in 5712:is not refutable for any 3076:is refutable, then so is 441:is needed to show this). 408:We approach the proof of 6793:. Thus for large enough 3049:{\displaystyle \varphi } 1804:{\displaystyle \varphi } 1760:{\displaystyle \varphi } 1425:{\displaystyle \varphi } 1405:{\displaystyle (P)\psi } 1252:{\displaystyle \varphi } 1237:Löwenheim–Skolem theorem 1228:{\displaystyle \varphi } 1208:{\displaystyle \varphi } 698:, and two new variables 7864:{\displaystyle \wedge } 7330:{\displaystyle \wedge } 6376:. Each i-ary predicate 6108:{\displaystyle E_{h-1}} 3644:{\displaystyle \wedge } 3624:{\displaystyle \wedge } 2959:is a formula of degree 586:, then certainly so is 8144: 8052: 8031:as above; then define 8025: 7993: 7949: 7923: 7894: 7865: 7844: 7601: 7574: 7331: 7310: 7186: 6679: 6652: 6526: 6499: 6436: 6390: 6366: 6336: 6305: 6278: 6247: 6220: 6193: 6166: 6136: 6109: 6076: 6045: 6018: 5991: 5964: 5937: 5910: 5883: 5856: 5822: 5795: 5768: 5741: 5706: 5681:is refutable for some 5675: 5641: 5351: 5315: 5220: 4844: 4801: 4689: 4662: 4499: 4469: 4413: 4353: 4301: 4255: 4157: 4065:should hold if either 4059: 3966: 3807:would not have been a 3801: 3781: 3684: 3645: 3625: 3602: 3358: 3333: 3280: 3190: 3162: 3136: 3113: 3090: 3070: 3050: 3030: 2977: 2953: 2930: 2896: 2713: 2647: 2590: 2404: 2247: 2194: 2165: 1981:respectively, and let 1956: 1916: 1857: 1805: 1785: 1767:(it is thus of degree 1761: 1734: 1633: 1432:(it is thus of degree 1426: 1406: 1377: 1253: 1229: 1209: 1182: 903: 877: 812: 649: 572: 167: ... ∃ 144: ... ∀ 21: 8174:, a weak form of AC. 8168:transfinite induction 8145: 8058:to be the closure of 8053: 8051:{\displaystyle D_{k}} 8026: 7994: 7950: 7924: 7895: 7866: 7845: 7602: 7575: 7332: 7311: 7187: 6689:Intuitive explanation 6680: 6678:{\displaystyle a^{n}} 6653: 6527: 6525:{\displaystyle D_{k}} 6500: 6437: 6391: 6389:{\displaystyle \Psi } 6367: 6365:{\displaystyle D_{k}} 6337: 6335:{\displaystyle D_{n}} 6306: 6304:{\displaystyle D_{k}} 6279: 6277:{\displaystyle E_{h}} 6248: 6246:{\displaystyle D_{n}} 6221: 6219:{\displaystyle B_{k}} 6194: 6192:{\displaystyle D_{k}} 6167: 6165:{\displaystyle B_{k}} 6142:in the same fashion. 6137: 6135:{\displaystyle E_{h}} 6110: 6077: 6075:{\displaystyle E_{1}} 6046: 6044:{\displaystyle E_{1}} 6019: 6017:{\displaystyle E_{1}} 5992: 5990:{\displaystyle E_{1}} 5965: 5963:{\displaystyle D_{n}} 5938: 5936:{\displaystyle D_{n}} 5911: 5909:{\displaystyle E_{h}} 5884: 5882:{\displaystyle D_{n}} 5857: 5855:{\displaystyle E_{h}} 5823: 5821:{\displaystyle D_{n}} 5796: 5794:{\displaystyle B_{k}} 5769: 5767:{\displaystyle D_{n}} 5742: 5740:{\displaystyle E_{h}} 5707: 5705:{\displaystyle D_{n}} 5676: 5674:{\displaystyle D_{n}} 5642: 5352: 5316: 5221: 4845: 4802: 4690: 4688:{\displaystyle D_{n}} 4663: 4500: 4498:{\displaystyle B_{n}} 4470: 4414: 4354: 4302: 4256: 4158: 4060: 3967: 3802: 3800:{\displaystyle \Psi } 3782: 3685: 3646: 3626: 3603: 3359: 3334: 3281: 3191: 3163: 3137: 3114: 3091: 3089:{\displaystyle \Phi } 3071: 3069:{\displaystyle \Psi } 3051: 3031: 2978: 2976:{\displaystyle \Psi } 2954: 2952:{\displaystyle \Psi } 2931: 2897: 2714: 2648: 2591: 2405: 2248: 2195: 2166: 1957: 1917: 1858: 1806: 1786: 1784:{\displaystyle \psi } 1762: 1735: 1634: 1440:so that for every x, 1427: 1407: 1378: 1254: 1230: 1210: 1183: 904: 878: 813: 650: 573: 19: 8258:MacTutor biography: 8062: 8035: 8003: 7976: 7933: 7907: 7876: 7855: 7612: 7585: 7342: 7321: 7195: 7038: 6662: 6539: 6509: 6446: 6400: 6380: 6349: 6319: 6288: 6261: 6230: 6203: 6176: 6149: 6119: 6086: 6059: 6028: 6001: 5974: 5947: 5920: 5893: 5866: 5839: 5805: 5778: 5751: 5724: 5689: 5658: 5364: 5325: 5230: 4864: 4821: 4702: 4672: 4509: 4482: 4423: 4367: 4311: 4265: 4167: 4069: 3991: 3834: 3791: 3701: 3671: 3635: 3615: 3371: 3345: 3290: 3200: 3177: 3149: 3123: 3100: 3080: 3060: 3040: 2991: 2987:, then, considering 2967: 2943: 2909: 2731: 2677: 2603: 2599:Now Φ' has the form 2420: 2268: 2207: 2178: 2000: 1926: 1867: 1838: 1795: 1775: 1771: – 1) and 1751: 1661: 1464: 1416: 1412:is the remainder of 1387: 1304: 1243: 1219: 1199: 932: 887: 822: 730: 598: 527: 368:is refutable" means 8300:Works by Kurt Gödel 8285:Mathematical proofs 8139: 8121: 8097: 8079: 8020: 6612: 6594: 5830:propositional logic 5468: 5443: 5360:For the base case, 5280: 5262: 5184: 5159: 5096: 5071: 4562: 4537: 4461: 4443: 4361:lexicographic order 3809:well-formed formula 1863:really stands for 594:is refutable, then 302:propositional logic 65:normal form theorem 8290:Mathematical logic 8214:10.1007/BF01696781 8140: 8125: 8107: 8083: 8065: 8048: 8021: 8006: 7989: 7945: 7919: 7890: 7861: 7840: 7597: 7570: 7327: 7306: 7182: 6693:We may write each 6675: 6648: 6598: 6580: 6522: 6495: 6432: 6386: 6362: 6332: 6301: 6274: 6243: 6216: 6189: 6162: 6132: 6105: 6072: 6041: 6014: 5987: 5960: 5933: 5906: 5889:will be true: The 5879: 5852: 5818: 5791: 5764: 5737: 5702: 5671: 5637: 5454: 5429: 5347: 5311: 5266: 5248: 5216: 5170: 5145: 5082: 5057: 4856:: By induction on 4840: 4797: 4685: 4658: 4548: 4523: 4495: 4465: 4447: 4429: 4409: 4349: 4297: 4251: 4153: 4055: 3962: 3797: 3777: 3680: 3641: 3621: 3598: 3354: 3329: 3276: 3186: 3158: 3132: 3109: 3086: 3066: 3046: 3026: 2973: 2949: 2926: 2892: 2709: 2643: 2586: 2400: 2243: 2190: 2161: 1952: 1912: 1853: 1801: 1781: 1757: 1730: 1629: 1422: 1402: 1373: 1249: 1225: 1205: 1178: 899: 873: 808: 645: 568: 35:mathematical logic 22: 6895:of these objects 3196:with the formula 2665:, no variable of 1292:: Take a formula 439:soundness theorem 69:soundness theorem 20:Kurt Gödel (1925) 8312: 8253:Juliette Kennedy 8233: 8192: 8149: 8147: 8146: 8141: 8138: 8133: 8120: 8115: 8096: 8091: 8078: 8073: 8057: 8055: 8054: 8049: 8047: 8046: 8030: 8028: 8027: 8022: 8019: 8014: 7998: 7996: 7995: 7990: 7988: 7987: 7954: 7952: 7951: 7946: 7928: 7926: 7925: 7920: 7899: 7897: 7896: 7891: 7886: 7870: 7868: 7867: 7862: 7849: 7847: 7846: 7841: 7830: 7829: 7817: 7816: 7795: 7794: 7782: 7781: 7754: 7753: 7741: 7740: 7710: 7709: 7697: 7696: 7669: 7668: 7656: 7655: 7643: 7642: 7630: 7629: 7606: 7604: 7603: 7598: 7579: 7577: 7576: 7571: 7560: 7559: 7547: 7546: 7525: 7524: 7512: 7511: 7484: 7483: 7471: 7470: 7440: 7439: 7427: 7426: 7399: 7398: 7386: 7385: 7373: 7372: 7360: 7359: 7336: 7334: 7333: 7328: 7315: 7313: 7312: 7307: 7191: 7189: 7188: 7183: 6947:, which makes Φ( 6684: 6682: 6681: 6676: 6674: 6673: 6657: 6655: 6654: 6649: 6644: 6643: 6625: 6624: 6611: 6606: 6593: 6588: 6570: 6569: 6557: 6556: 6531: 6529: 6528: 6523: 6521: 6520: 6504: 6502: 6501: 6496: 6491: 6490: 6489: 6488: 6471: 6470: 6469: 6468: 6441: 6439: 6438: 6433: 6428: 6427: 6415: 6414: 6395: 6393: 6392: 6387: 6371: 6369: 6368: 6363: 6361: 6360: 6341: 6339: 6338: 6333: 6331: 6330: 6310: 6308: 6307: 6302: 6300: 6299: 6283: 6281: 6280: 6275: 6273: 6272: 6252: 6250: 6249: 6244: 6242: 6241: 6225: 6223: 6222: 6217: 6215: 6214: 6198: 6196: 6195: 6190: 6188: 6187: 6171: 6169: 6168: 6163: 6161: 6160: 6141: 6139: 6138: 6133: 6131: 6130: 6114: 6112: 6111: 6106: 6104: 6103: 6081: 6079: 6078: 6073: 6071: 6070: 6050: 6048: 6047: 6042: 6040: 6039: 6023: 6021: 6020: 6015: 6013: 6012: 5996: 5994: 5993: 5988: 5986: 5985: 5969: 5967: 5966: 5961: 5959: 5958: 5942: 5940: 5939: 5934: 5932: 5931: 5915: 5913: 5912: 5907: 5905: 5904: 5888: 5886: 5885: 5880: 5878: 5877: 5861: 5859: 5858: 5853: 5851: 5850: 5827: 5825: 5824: 5819: 5817: 5816: 5800: 5798: 5797: 5792: 5790: 5789: 5773: 5771: 5770: 5765: 5763: 5762: 5746: 5744: 5743: 5738: 5736: 5735: 5716:. Then for each 5711: 5709: 5708: 5703: 5701: 5700: 5680: 5678: 5677: 5672: 5670: 5669: 5646: 5644: 5643: 5638: 5633: 5632: 5614: 5613: 5601: 5600: 5588: 5587: 5575: 5574: 5556: 5555: 5537: 5536: 5515: 5514: 5496: 5495: 5483: 5482: 5470: 5469: 5467: 5462: 5445: 5444: 5442: 5437: 5414: 5413: 5395: 5394: 5376: 5375: 5356: 5354: 5353: 5348: 5343: 5342: 5320: 5318: 5317: 5312: 5279: 5274: 5261: 5256: 5225: 5223: 5222: 5217: 5212: 5211: 5199: 5198: 5186: 5185: 5183: 5178: 5161: 5160: 5158: 5153: 5130: 5129: 5117: 5116: 5098: 5097: 5095: 5090: 5073: 5072: 5070: 5065: 5042: 5041: 5023: 5022: 5010: 5009: 4988: 4987: 4948: 4947: 4914: 4913: 4895: 4894: 4876: 4875: 4849: 4847: 4846: 4841: 4839: 4838: 4806: 4804: 4803: 4798: 4790: 4789: 4771: 4770: 4758: 4757: 4742: 4741: 4720: 4719: 4694: 4692: 4691: 4686: 4684: 4683: 4667: 4665: 4664: 4659: 4654: 4653: 4632: 4631: 4598: 4597: 4564: 4563: 4561: 4556: 4539: 4538: 4536: 4531: 4504: 4502: 4501: 4496: 4494: 4493: 4478:Set the formula 4474: 4472: 4471: 4466: 4460: 4455: 4442: 4437: 4418: 4416: 4415: 4410: 4405: 4404: 4392: 4391: 4379: 4378: 4358: 4356: 4355: 4350: 4345: 4344: 4326: 4325: 4306: 4304: 4303: 4298: 4293: 4292: 4280: 4279: 4260: 4258: 4257: 4252: 4247: 4246: 4234: 4233: 4221: 4220: 4205: 4204: 4192: 4191: 4179: 4178: 4162: 4160: 4159: 4154: 4149: 4148: 4136: 4135: 4123: 4122: 4107: 4106: 4094: 4093: 4081: 4080: 4064: 4062: 4061: 4056: 4051: 4050: 4038: 4037: 4019: 4018: 4006: 4005: 3971: 3969: 3968: 3963: 3955: 3954: 3942: 3941: 3929: 3928: 3916: 3915: 3897: 3896: 3884: 3883: 3865: 3864: 3852: 3851: 3819:As shown by the 3806: 3804: 3803: 3798: 3786: 3784: 3783: 3778: 3773: 3762: 3689: 3687: 3686: 3681: 3650: 3648: 3647: 3642: 3630: 3628: 3627: 3622: 3607: 3605: 3604: 3599: 3483: 3472: 3410: 3393: 3363: 3361: 3360: 3355: 3338: 3336: 3335: 3330: 3285: 3283: 3282: 3277: 3272: 3261: 3195: 3193: 3192: 3187: 3167: 3165: 3164: 3159: 3141: 3139: 3138: 3133: 3118: 3116: 3115: 3110: 3095: 3093: 3092: 3087: 3075: 3073: 3072: 3067: 3055: 3053: 3052: 3047: 3035: 3033: 3032: 3027: 3007: 2982: 2980: 2979: 2974: 2958: 2956: 2955: 2950: 2935: 2933: 2932: 2927: 2919: 2901: 2899: 2898: 2893: 2855: 2844: 2806: 2753: 2718: 2716: 2715: 2710: 2705: 2652: 2650: 2649: 2644: 2642: 2631: 2595: 2593: 2592: 2587: 2492: 2481: 2464: 2447: 2430: 2409: 2407: 2406: 2401: 2252: 2250: 2249: 2244: 2199: 2197: 2196: 2191: 2170: 2168: 2167: 2162: 2067: 2056: 2039: 2022: 1961: 1959: 1958: 1953: 1951: 1950: 1938: 1937: 1921: 1919: 1918: 1913: 1911: 1910: 1895: 1894: 1882: 1881: 1862: 1860: 1859: 1854: 1810: 1808: 1807: 1802: 1790: 1788: 1787: 1782: 1766: 1764: 1763: 1758: 1739: 1737: 1736: 1731: 1638: 1636: 1635: 1630: 1604: 1587: 1576: 1565: 1545: 1480: 1431: 1429: 1428: 1423: 1411: 1409: 1408: 1403: 1382: 1380: 1379: 1374: 1285: + 1. 1258: 1256: 1255: 1250: 1234: 1232: 1231: 1226: 1214: 1212: 1211: 1206: 1187: 1185: 1184: 1179: 1165: 1164: 1163: 1162: 1142: 1141: 1134: 1133: 1104: 1103: 1102: 1101: 1075: 1074: 1067: 1066: 1034: 1033: 1032: 1031: 1011: 1010: 1003: 1002: 979: 978: 977: 976: 956: 955: 908: 906: 905: 900: 882: 880: 879: 874: 817: 815: 814: 809: 654: 652: 651: 646: 638: 637: 622: 621: 577: 575: 574: 569: 564: 563: 548: 547: 496:in normal form. 295: 212: 124: 120: 116: 112: 105:, i.e. with all 80:without identity 76:without equality 8320: 8319: 8315: 8314: 8313: 8311: 8310: 8309: 8265: 8264: 8241: 8196: 8183: 8180: 8160:Axiom of Choice 8156: 8060: 8059: 8038: 8033: 8032: 8001: 8000: 7979: 7974: 7973: 7969: 7931: 7930: 7905: 7904: 7879: 7874: 7873: 7853: 7852: 7821: 7808: 7786: 7773: 7745: 7732: 7701: 7688: 7660: 7647: 7634: 7621: 7610: 7609: 7583: 7582: 7551: 7538: 7516: 7503: 7475: 7462: 7431: 7418: 7390: 7377: 7364: 7351: 7340: 7339: 7319: 7318: 7193: 7192: 7036: 7035: 7028: 7023: 7012: 7005: 6998: 6997: 6984: 6983: 6972: 6971: 6958: 6957: 6946: 6945: 6932: 6931: 6920: 6919: 6906: 6905: 6890: 6877: 6870: 6863: 6851: 6850: 6844: 6840: 6831: 6818: 6811: 6810: 6799: 6792: 6775: 6765: 6758: 6751: 6733: 6724: 6717: 6708: 6701: 6691: 6665: 6660: 6659: 6635: 6616: 6561: 6548: 6537: 6536: 6512: 6507: 6506: 6480: 6475: 6460: 6455: 6444: 6443: 6419: 6406: 6398: 6397: 6378: 6377: 6374:natural numbers 6352: 6347: 6346: 6322: 6317: 6316: 6291: 6286: 6285: 6264: 6259: 6258: 6233: 6228: 6227: 6206: 6201: 6200: 6179: 6174: 6173: 6152: 6147: 6146: 6122: 6117: 6116: 6089: 6084: 6083: 6062: 6057: 6056: 6031: 6026: 6025: 6004: 5999: 5998: 5977: 5972: 5971: 5950: 5945: 5944: 5923: 5918: 5917: 5896: 5891: 5890: 5869: 5864: 5863: 5842: 5837: 5836: 5808: 5803: 5802: 5781: 5776: 5775: 5754: 5749: 5748: 5727: 5722: 5721: 5692: 5687: 5686: 5661: 5656: 5655: 5618: 5605: 5592: 5579: 5566: 5541: 5528: 5500: 5487: 5474: 5449: 5424: 5399: 5386: 5367: 5362: 5361: 5328: 5323: 5322: 5228: 5227: 5203: 5190: 5165: 5140: 5121: 5108: 5077: 5052: 5027: 5014: 4992: 4958: 4918: 4905: 4880: 4867: 4862: 4861: 4830: 4819: 4818: 4781: 4762: 4749: 4724: 4711: 4700: 4699: 4675: 4670: 4669: 4636: 4602: 4568: 4543: 4518: 4507: 4506: 4485: 4480: 4479: 4421: 4420: 4396: 4383: 4370: 4365: 4364: 4336: 4317: 4309: 4308: 4284: 4271: 4263: 4262: 4238: 4225: 4212: 4196: 4183: 4170: 4165: 4164: 4140: 4127: 4114: 4098: 4085: 4072: 4067: 4066: 4042: 4029: 4010: 3997: 3989: 3988: 3985:natural numbers 3946: 3933: 3920: 3907: 3888: 3875: 3856: 3843: 3832: 3831: 3817: 3789: 3788: 3766: 3755: 3699: 3698: 3669: 3668: 3633: 3632: 3613: 3612: 3476: 3465: 3403: 3386: 3369: 3368: 3343: 3342: 3288: 3287: 3265: 3254: 3198: 3197: 3175: 3174: 3147: 3146: 3121: 3120: 3098: 3097: 3078: 3077: 3058: 3057: 3038: 3037: 3000: 2989: 2988: 2965: 2964: 2941: 2940: 2912: 2907: 2906: 2848: 2837: 2799: 2746: 2729: 2728: 2698: 2675: 2674: 2635: 2624: 2601: 2600: 2485: 2474: 2457: 2440: 2423: 2418: 2417: 2266: 2265: 2205: 2204: 2176: 2175: 2060: 2049: 2032: 2015: 1998: 1997: 1942: 1929: 1924: 1923: 1902: 1886: 1873: 1865: 1864: 1836: 1835: 1793: 1792: 1773: 1772: 1749: 1748: 1659: 1658: 1597: 1580: 1569: 1558: 1538: 1473: 1462: 1461: 1414: 1413: 1385: 1384: 1302: 1301: 1241: 1240: 1217: 1216: 1197: 1196: 1154: 1149: 1119: 1114: 1087: 1082: 1052: 1047: 1023: 1018: 994: 989: 968: 963: 947: 930: 929: 915: 885: 884: 820: 819: 728: 727: 629: 613: 596: 595: 555: 539: 525: 524: 518: 509: 406: 382: 362: 353: 339: 315: 293: 292: 286: 285: 279: 278: 272: 271: 265: 264: 258: 257: 251: 250: 244: 243: 237: 236: 230: 229: 223: 220: 210: 202: ...  201: 194: 186: ...  185: 175: 166: 159: 152: 143: 136: 129: 122: 118: 114: 110: 92: 43: 12: 11: 5: 8318: 8316: 8308: 8307: 8305:Article proofs 8302: 8297: 8292: 8287: 8282: 8277: 8267: 8266: 8263: 8262: 8256: 8240: 8239:External links 8237: 8236: 8235: 8208:(1): 349–360. 8194: 8179: 8176: 8155: 8152: 8137: 8132: 8128: 8124: 8119: 8114: 8110: 8106: 8103: 8100: 8095: 8090: 8086: 8082: 8077: 8072: 8068: 8045: 8041: 8018: 8013: 8009: 7986: 7982: 7968: 7965: 7944: 7941: 7938: 7918: 7915: 7912: 7901: 7900: 7889: 7885: 7882: 7871: 7860: 7850: 7839: 7836: 7833: 7828: 7824: 7820: 7815: 7811: 7807: 7804: 7801: 7798: 7793: 7789: 7785: 7780: 7776: 7772: 7769: 7766: 7763: 7760: 7757: 7752: 7748: 7744: 7739: 7735: 7731: 7728: 7725: 7722: 7719: 7716: 7713: 7708: 7704: 7700: 7695: 7691: 7687: 7684: 7681: 7678: 7675: 7672: 7667: 7663: 7659: 7654: 7650: 7646: 7641: 7637: 7633: 7628: 7624: 7620: 7617: 7607: 7596: 7593: 7590: 7580: 7569: 7566: 7563: 7558: 7554: 7550: 7545: 7541: 7537: 7534: 7531: 7528: 7523: 7519: 7515: 7510: 7506: 7502: 7499: 7496: 7493: 7490: 7487: 7482: 7478: 7474: 7469: 7465: 7461: 7458: 7455: 7452: 7449: 7446: 7443: 7438: 7434: 7430: 7425: 7421: 7417: 7414: 7411: 7408: 7405: 7402: 7397: 7393: 7389: 7384: 7380: 7376: 7371: 7367: 7363: 7358: 7354: 7350: 7347: 7337: 7326: 7316: 7305: 7302: 7299: 7296: 7293: 7290: 7287: 7284: 7281: 7278: 7275: 7272: 7269: 7266: 7263: 7260: 7257: 7254: 7251: 7248: 7245: 7242: 7239: 7236: 7233: 7230: 7227: 7224: 7221: 7218: 7215: 7212: 7209: 7206: 7203: 7200: 7181: 7178: 7175: 7172: 7169: 7166: 7163: 7160: 7157: 7154: 7151: 7148: 7145: 7142: 7139: 7136: 7133: 7130: 7127: 7124: 7121: 7118: 7115: 7112: 7109: 7106: 7103: 7100: 7097: 7094: 7091: 7088: 7085: 7082: 7079: 7076: 7073: 7070: 7067: 7064: 7061: 7058: 7055: 7052: 7049: 7046: 7043: 7027: 7024: 7022: 7019: 7010: 7003: 6993: 6989: 6981: 6977: 6967: 6963: 6955: 6951: 6941: 6937: 6929: 6925: 6915: 6911: 6903: 6899: 6886: 6875: 6868: 6859: 6848: 6846: 6842: 6836: 6827: 6816: 6808: 6804: 6797: 6788: 6770: 6763: 6756: 6749: 6729: 6722: 6713: 6706: 6697: 6690: 6687: 6672: 6668: 6647: 6642: 6638: 6634: 6631: 6628: 6623: 6619: 6615: 6610: 6605: 6601: 6597: 6592: 6587: 6583: 6579: 6576: 6573: 6568: 6564: 6560: 6555: 6551: 6547: 6544: 6519: 6515: 6494: 6487: 6483: 6478: 6474: 6467: 6463: 6458: 6454: 6451: 6431: 6426: 6422: 6418: 6413: 6409: 6405: 6385: 6359: 6355: 6329: 6325: 6298: 6294: 6271: 6267: 6240: 6236: 6213: 6209: 6186: 6182: 6159: 6155: 6129: 6125: 6102: 6099: 6096: 6092: 6069: 6065: 6038: 6034: 6011: 6007: 5984: 5980: 5957: 5953: 5930: 5926: 5903: 5899: 5876: 5872: 5862:, so that all 5849: 5845: 5815: 5811: 5788: 5784: 5761: 5757: 5734: 5730: 5699: 5695: 5668: 5664: 5636: 5631: 5628: 5625: 5621: 5617: 5612: 5608: 5604: 5599: 5595: 5591: 5586: 5582: 5578: 5573: 5569: 5565: 5562: 5559: 5554: 5551: 5548: 5544: 5540: 5535: 5531: 5527: 5524: 5521: 5518: 5513: 5510: 5507: 5503: 5499: 5494: 5490: 5486: 5481: 5477: 5473: 5466: 5461: 5457: 5452: 5448: 5441: 5436: 5432: 5427: 5423: 5420: 5417: 5412: 5409: 5406: 5402: 5398: 5393: 5389: 5385: 5382: 5379: 5374: 5370: 5346: 5341: 5338: 5335: 5331: 5310: 5307: 5304: 5301: 5298: 5295: 5292: 5289: 5286: 5283: 5278: 5273: 5269: 5265: 5260: 5255: 5251: 5247: 5244: 5241: 5238: 5235: 5215: 5210: 5206: 5202: 5197: 5193: 5189: 5182: 5177: 5173: 5168: 5164: 5157: 5152: 5148: 5143: 5139: 5136: 5133: 5128: 5124: 5120: 5115: 5111: 5107: 5104: 5101: 5094: 5089: 5085: 5080: 5076: 5069: 5064: 5060: 5055: 5051: 5048: 5045: 5040: 5037: 5034: 5030: 5026: 5021: 5017: 5013: 5008: 5005: 5002: 4999: 4995: 4991: 4986: 4983: 4980: 4977: 4974: 4971: 4968: 4965: 4961: 4957: 4954: 4951: 4946: 4943: 4940: 4937: 4934: 4931: 4928: 4925: 4921: 4917: 4912: 4908: 4904: 4901: 4898: 4893: 4890: 4887: 4883: 4879: 4874: 4870: 4837: 4833: 4829: 4826: 4808: 4807: 4796: 4793: 4788: 4784: 4780: 4777: 4774: 4769: 4765: 4761: 4756: 4752: 4748: 4745: 4740: 4737: 4734: 4731: 4727: 4723: 4718: 4714: 4710: 4707: 4682: 4678: 4657: 4652: 4649: 4646: 4643: 4639: 4635: 4630: 4627: 4624: 4621: 4618: 4615: 4612: 4609: 4605: 4601: 4596: 4593: 4590: 4587: 4584: 4581: 4578: 4575: 4571: 4567: 4560: 4555: 4551: 4546: 4542: 4535: 4530: 4526: 4521: 4517: 4514: 4492: 4488: 4464: 4459: 4454: 4450: 4446: 4441: 4436: 4432: 4428: 4408: 4403: 4399: 4395: 4390: 4386: 4382: 4377: 4373: 4348: 4343: 4339: 4335: 4332: 4329: 4324: 4320: 4316: 4296: 4291: 4287: 4283: 4278: 4274: 4270: 4250: 4245: 4241: 4237: 4232: 4228: 4224: 4219: 4215: 4211: 4208: 4203: 4199: 4195: 4190: 4186: 4182: 4177: 4173: 4152: 4147: 4143: 4139: 4134: 4130: 4126: 4121: 4117: 4113: 4110: 4105: 4101: 4097: 4092: 4088: 4084: 4079: 4075: 4054: 4049: 4045: 4041: 4036: 4032: 4028: 4025: 4022: 4017: 4013: 4009: 4004: 4000: 3996: 3973: 3972: 3961: 3958: 3953: 3949: 3945: 3940: 3936: 3932: 3927: 3923: 3919: 3914: 3910: 3906: 3903: 3900: 3895: 3891: 3887: 3882: 3878: 3874: 3871: 3868: 3863: 3859: 3855: 3850: 3846: 3842: 3839: 3816: 3813: 3796: 3776: 3772: 3769: 3765: 3761: 3758: 3754: 3751: 3748: 3745: 3742: 3739: 3736: 3733: 3730: 3727: 3724: 3721: 3718: 3715: 3712: 3709: 3706: 3679: 3676: 3667:, we see that 3640: 3620: 3609: 3608: 3597: 3594: 3591: 3588: 3585: 3582: 3579: 3576: 3573: 3570: 3567: 3564: 3561: 3558: 3555: 3552: 3549: 3546: 3543: 3540: 3537: 3534: 3531: 3528: 3525: 3522: 3519: 3516: 3513: 3510: 3507: 3504: 3501: 3498: 3495: 3492: 3489: 3486: 3482: 3479: 3475: 3471: 3468: 3464: 3461: 3458: 3455: 3452: 3449: 3446: 3443: 3440: 3437: 3434: 3431: 3428: 3425: 3422: 3419: 3416: 3413: 3409: 3406: 3402: 3399: 3396: 3392: 3389: 3385: 3382: 3379: 3376: 3353: 3350: 3328: 3325: 3322: 3319: 3316: 3313: 3310: 3307: 3304: 3301: 3298: 3295: 3275: 3271: 3268: 3264: 3260: 3257: 3253: 3250: 3247: 3244: 3241: 3238: 3235: 3232: 3229: 3226: 3223: 3220: 3217: 3214: 3211: 3208: 3205: 3185: 3182: 3157: 3154: 3131: 3128: 3108: 3105: 3085: 3065: 3045: 3036:, we see that 3025: 3022: 3019: 3016: 3013: 3010: 3006: 3003: 2999: 2996: 2972: 2948: 2925: 2922: 2918: 2915: 2903: 2902: 2891: 2888: 2885: 2882: 2879: 2876: 2873: 2870: 2867: 2864: 2861: 2858: 2854: 2851: 2847: 2843: 2840: 2836: 2833: 2830: 2827: 2824: 2821: 2818: 2815: 2812: 2809: 2805: 2802: 2798: 2795: 2792: 2789: 2786: 2783: 2780: 2777: 2774: 2771: 2768: 2765: 2762: 2759: 2756: 2752: 2749: 2745: 2742: 2739: 2736: 2708: 2704: 2701: 2697: 2694: 2691: 2688: 2685: 2682: 2641: 2638: 2634: 2630: 2627: 2623: 2620: 2617: 2614: 2611: 2608: 2597: 2596: 2585: 2582: 2579: 2576: 2573: 2570: 2567: 2564: 2561: 2558: 2555: 2552: 2549: 2546: 2543: 2540: 2537: 2534: 2531: 2528: 2525: 2522: 2519: 2516: 2513: 2510: 2507: 2504: 2501: 2498: 2495: 2491: 2488: 2484: 2480: 2477: 2473: 2470: 2467: 2463: 2460: 2456: 2453: 2450: 2446: 2443: 2439: 2436: 2433: 2429: 2426: 2411: 2410: 2399: 2396: 2393: 2390: 2387: 2384: 2381: 2378: 2375: 2372: 2369: 2366: 2363: 2360: 2357: 2354: 2351: 2348: 2345: 2342: 2339: 2336: 2333: 2330: 2327: 2324: 2321: 2318: 2315: 2312: 2309: 2306: 2303: 2300: 2297: 2294: 2291: 2288: 2285: 2282: 2279: 2276: 2273: 2242: 2239: 2236: 2233: 2230: 2227: 2224: 2221: 2218: 2215: 2212: 2189: 2186: 2183: 2172: 2171: 2160: 2157: 2154: 2151: 2148: 2145: 2142: 2139: 2136: 2133: 2130: 2127: 2124: 2121: 2118: 2115: 2112: 2109: 2106: 2103: 2100: 2097: 2094: 2091: 2088: 2085: 2082: 2079: 2076: 2073: 2070: 2066: 2063: 2059: 2055: 2052: 2048: 2045: 2042: 2038: 2035: 2031: 2028: 2025: 2021: 2018: 2014: 2011: 2008: 2005: 1949: 1945: 1941: 1936: 1932: 1909: 1905: 1901: 1898: 1893: 1889: 1885: 1880: 1876: 1872: 1852: 1849: 1846: 1843: 1800: 1780: 1756: 1741: 1740: 1729: 1726: 1723: 1720: 1717: 1714: 1711: 1708: 1705: 1702: 1699: 1696: 1693: 1690: 1687: 1684: 1681: 1678: 1675: 1672: 1669: 1666: 1645: 1644: 1628: 1625: 1622: 1619: 1616: 1613: 1610: 1607: 1603: 1600: 1596: 1593: 1590: 1586: 1583: 1579: 1575: 1572: 1568: 1564: 1561: 1557: 1554: 1551: 1548: 1544: 1541: 1537: 1534: 1531: 1528: 1525: 1522: 1519: 1516: 1513: 1510: 1507: 1504: 1501: 1498: 1495: 1492: 1489: 1486: 1483: 1479: 1476: 1472: 1469: 1421: 1401: 1398: 1395: 1392: 1372: 1369: 1366: 1363: 1360: 1357: 1354: 1351: 1348: 1345: 1342: 1339: 1336: 1333: 1330: 1327: 1324: 1321: 1318: 1315: 1312: 1309: 1248: 1224: 1204: 1191:We define the 1189: 1188: 1177: 1174: 1171: 1168: 1161: 1157: 1152: 1148: 1145: 1140: 1137: 1132: 1129: 1126: 1122: 1117: 1113: 1110: 1107: 1100: 1097: 1094: 1090: 1085: 1081: 1078: 1073: 1070: 1065: 1062: 1059: 1055: 1050: 1046: 1043: 1040: 1037: 1030: 1026: 1021: 1017: 1014: 1009: 1006: 1001: 997: 992: 988: 985: 982: 975: 971: 966: 962: 959: 954: 950: 946: 943: 940: 937: 914: 911: 898: 895: 892: 872: 869: 866: 863: 860: 857: 854: 851: 848: 845: 842: 839: 836: 833: 830: 827: 807: 804: 801: 798: 795: 792: 789: 786: 783: 780: 777: 774: 771: 768: 765: 762: 759: 756: 753: 750: 747: 744: 741: 738: 735: 718:and Φ for the 644: 641: 636: 632: 628: 625: 620: 616: 612: 609: 606: 603: 567: 562: 558: 554: 551: 546: 542: 538: 535: 532: 514: 507: 405: 402: 381: 378: 376:is provable". 361: 358: 352: 349: 348: 347: 346: 345: 335: 329: 311: 305: 290: 288: 283: 281: 276: 274: 269: 267: 262: 260: 255: 253: 248: 246: 241: 239: 234: 232: 227: 225: 221: 214: 206: 199: 190: 183: 171: 164: 157: 148: 141: 134: 126: 91: 88: 42: 39: 13: 10: 9: 6: 4: 3: 2: 8317: 8306: 8303: 8301: 8298: 8296: 8293: 8291: 8288: 8286: 8283: 8281: 8278: 8276: 8273: 8272: 8270: 8261: 8257: 8254: 8250: 8246: 8243: 8242: 8238: 8231: 8227: 8223: 8219: 8215: 8211: 8207: 8204:(in German). 8203: 8199: 8195: 8190: 8186: 8182: 8181: 8177: 8175: 8173: 8169: 8165: 8161: 8153: 8151: 8135: 8130: 8126: 8122: 8117: 8112: 8108: 8104: 8101: 8098: 8093: 8088: 8084: 8080: 8075: 8070: 8066: 8043: 8039: 8016: 8011: 8007: 7984: 7980: 7966: 7964: 7962: 7958: 7942: 7939: 7936: 7916: 7913: 7910: 7887: 7883: 7880: 7872: 7858: 7851: 7826: 7822: 7818: 7813: 7809: 7802: 7799: 7791: 7787: 7783: 7778: 7774: 7767: 7750: 7746: 7742: 7737: 7733: 7726: 7723: 7720: 7717: 7714: 7706: 7702: 7698: 7693: 7689: 7682: 7679: 7665: 7661: 7657: 7652: 7648: 7644: 7639: 7635: 7631: 7626: 7622: 7608: 7594: 7591: 7588: 7581: 7556: 7552: 7548: 7543: 7539: 7532: 7529: 7521: 7517: 7513: 7508: 7504: 7497: 7480: 7476: 7472: 7467: 7463: 7456: 7453: 7450: 7447: 7444: 7436: 7432: 7428: 7423: 7419: 7412: 7409: 7395: 7391: 7387: 7382: 7378: 7374: 7369: 7365: 7361: 7356: 7352: 7338: 7324: 7317: 7294: 7291: 7288: 7282: 7279: 7270: 7267: 7264: 7258: 7255: 7243: 7240: 7237: 7231: 7228: 7219: 7216: 7213: 7210: 7207: 7198: 7170: 7167: 7164: 7158: 7155: 7146: 7143: 7140: 7134: 7131: 7119: 7116: 7113: 7107: 7104: 7095: 7092: 7089: 7086: 7083: 7074: 7068: 7065: 7062: 7056: 7053: 7047: 7034: 7033: 7032: 7025: 7020: 7018: 7016: 7009: 7002: 6996: 6992: 6988: 6980: 6976: 6970: 6966: 6962: 6954: 6950: 6944: 6940: 6936: 6928: 6924: 6918: 6914: 6910: 6902: 6898: 6894: 6889: 6885: 6881: 6874: 6867: 6862: 6858: 6853: 6841:. For every B 6839: 6835: 6830: 6826: 6822: 6815: 6807: 6803: 6796: 6791: 6787: 6783: 6779: 6773: 6769: 6762: 6755: 6748: 6743: 6741: 6737: 6732: 6728: 6721: 6716: 6712: 6705: 6700: 6696: 6688: 6686: 6670: 6666: 6640: 6636: 6632: 6629: 6626: 6621: 6617: 6613: 6608: 6603: 6599: 6595: 6590: 6585: 6581: 6574: 6566: 6562: 6558: 6553: 6549: 6533: 6517: 6513: 6485: 6481: 6476: 6472: 6465: 6461: 6456: 6424: 6420: 6416: 6411: 6407: 6375: 6357: 6353: 6343: 6327: 6323: 6314: 6296: 6292: 6269: 6265: 6256: 6238: 6234: 6211: 6207: 6184: 6180: 6157: 6153: 6143: 6127: 6123: 6100: 6097: 6094: 6090: 6067: 6063: 6054: 6036: 6032: 6009: 6005: 5982: 5978: 5955: 5951: 5928: 5924: 5901: 5897: 5874: 5870: 5847: 5843: 5833: 5831: 5813: 5809: 5786: 5782: 5759: 5755: 5732: 5728: 5719: 5715: 5697: 5693: 5684: 5666: 5662: 5652: 5650: 5629: 5626: 5623: 5619: 5615: 5610: 5606: 5602: 5597: 5593: 5589: 5584: 5580: 5576: 5571: 5567: 5560: 5552: 5549: 5546: 5542: 5538: 5533: 5529: 5519: 5511: 5508: 5505: 5501: 5497: 5492: 5488: 5484: 5479: 5475: 5471: 5464: 5459: 5455: 5450: 5446: 5439: 5434: 5430: 5425: 5418: 5410: 5407: 5404: 5400: 5396: 5391: 5387: 5377: 5372: 5368: 5358: 5344: 5339: 5336: 5333: 5329: 5308: 5305: 5302: 5296: 5293: 5290: 5284: 5276: 5271: 5267: 5263: 5258: 5253: 5249: 5239: 5208: 5204: 5200: 5195: 5191: 5187: 5180: 5175: 5171: 5166: 5162: 5155: 5150: 5146: 5141: 5134: 5126: 5122: 5118: 5113: 5109: 5092: 5087: 5083: 5078: 5074: 5067: 5062: 5058: 5053: 5043: 5038: 5035: 5032: 5028: 5019: 5015: 5006: 5003: 5000: 4997: 4993: 4989: 4984: 4981: 4978: 4972: 4969: 4966: 4959: 4944: 4941: 4938: 4932: 4929: 4926: 4919: 4915: 4910: 4906: 4896: 4891: 4888: 4885: 4881: 4872: 4868: 4859: 4855: 4851: 4835: 4831: 4824: 4816: 4812: 4794: 4786: 4782: 4778: 4775: 4772: 4767: 4763: 4759: 4754: 4750: 4738: 4735: 4732: 4729: 4725: 4721: 4716: 4712: 4698: 4697: 4696: 4680: 4676: 4650: 4647: 4644: 4641: 4637: 4633: 4628: 4625: 4622: 4616: 4613: 4610: 4603: 4599: 4594: 4591: 4588: 4582: 4579: 4576: 4569: 4565: 4558: 4553: 4549: 4544: 4540: 4533: 4528: 4524: 4519: 4512: 4490: 4486: 4476: 4457: 4452: 4448: 4444: 4439: 4434: 4430: 4401: 4397: 4393: 4388: 4384: 4375: 4362: 4341: 4337: 4333: 4330: 4327: 4322: 4318: 4289: 4285: 4281: 4276: 4272: 4243: 4239: 4235: 4230: 4226: 4217: 4209: 4201: 4197: 4193: 4188: 4184: 4175: 4145: 4141: 4137: 4132: 4128: 4119: 4111: 4103: 4099: 4095: 4090: 4086: 4077: 4047: 4043: 4039: 4034: 4030: 4023: 4015: 4011: 4007: 4002: 3998: 3986: 3982: 3978: 3959: 3951: 3947: 3943: 3938: 3934: 3930: 3925: 3921: 3917: 3912: 3908: 3901: 3893: 3889: 3885: 3880: 3876: 3861: 3857: 3853: 3848: 3844: 3830: 3829: 3828: 3826: 3822: 3814: 3812: 3810: 3770: 3767: 3763: 3759: 3756: 3752: 3749: 3746: 3743: 3737: 3731: 3722: 3710: 3695: 3693: 3677: 3666: 3662: 3658: 3654: 3638: 3618: 3589: 3583: 3574: 3562: 3550: 3544: 3535: 3523: 3508: 3496: 3487: 3480: 3477: 3473: 3469: 3466: 3462: 3459: 3456: 3453: 3447: 3441: 3432: 3420: 3407: 3404: 3390: 3387: 3367: 3366: 3365: 3364:then becomes 3340: 3326: 3320: 3311: 3299: 3269: 3266: 3262: 3258: 3255: 3251: 3248: 3245: 3242: 3236: 3230: 3221: 3209: 3171: 3169: 3043: 3023: 3014: 3008: 3004: 2997: 2986: 2962: 2937: 2920: 2916: 2886: 2877: 2874: 2871: 2865: 2859: 2852: 2849: 2845: 2841: 2838: 2831: 2825: 2816: 2803: 2800: 2787: 2775: 2763: 2750: 2747: 2737: 2727: 2726: 2725: 2722: 2702: 2699: 2695: 2692: 2683: 2672: 2668: 2664: 2660: 2656: 2639: 2636: 2628: 2625: 2618: 2615: 2609: 2580: 2571: 2568: 2565: 2559: 2550: 2541: 2529: 2517: 2505: 2496: 2489: 2486: 2482: 2478: 2475: 2468: 2461: 2458: 2444: 2441: 2431: 2427: 2416: 2415: 2414: 2394: 2385: 2382: 2379: 2373: 2364: 2355: 2343: 2334: 2328: 2322: 2313: 2301: 2286: 2283: 2280: 2274: 2264: 2263: 2262: 2260: 2256: 2237: 2228: 2216: 2201: 2200:is provable. 2187: 2155: 2149: 2140: 2128: 2113: 2110: 2107: 2101: 2092: 2080: 2071: 2064: 2061: 2057: 2053: 2050: 2043: 2036: 2033: 2019: 2016: 2006: 1996: 1995: 1994: 1992: 1988: 1984: 1980: 1976: 1972: 1968: 1963: 1947: 1943: 1939: 1934: 1930: 1907: 1903: 1896: 1891: 1887: 1878: 1874: 1847: 1834: 1830: 1826: 1822: 1818: 1814: 1798: 1778: 1770: 1754: 1746: 1727: 1721: 1712: 1700: 1688: 1676: 1667: 1664: 1657: 1656: 1655: 1653: 1649: 1642: 1641:Unfortunately 1623: 1614: 1611: 1608: 1601: 1598: 1591: 1584: 1581: 1577: 1573: 1570: 1562: 1559: 1552: 1542: 1539: 1526: 1514: 1502: 1490: 1477: 1474: 1459: 1455: 1451: 1447: 1443: 1439: 1435: 1419: 1399: 1393: 1370: 1364: 1355: 1343: 1331: 1319: 1310: 1307: 1299: 1295: 1291: 1288: 1287: 1286: 1284: 1280: 1276: 1272: 1268: 1264: 1260: 1246: 1238: 1222: 1202: 1194: 1159: 1155: 1150: 1143: 1138: 1135: 1130: 1127: 1124: 1120: 1115: 1098: 1095: 1092: 1088: 1083: 1076: 1071: 1068: 1063: 1060: 1057: 1053: 1048: 1038: 1028: 1024: 1019: 1012: 1007: 1004: 999: 995: 990: 973: 969: 964: 957: 952: 948: 938: 935: 928: 927: 926: 924: 920: 912: 910: 909:is provable. 896: 893: 890: 864: 858: 852: 846: 840: 834: 828: 796: 790: 784: 778: 772: 766: 757: 748: 742: 736: 733: 725: 721: 717: 713: 709: 705: 701: 697: 693: 689: 685: 681: 677: 672: 670: 666: 662: 658: 642: 634: 630: 623: 618: 614: 607: 604: 593: 589: 585: 581: 565: 560: 556: 549: 544: 540: 533: 530: 522: 517: 513: 506: 502: 497: 495: 492:for formulas 491: 487: 483: 479: 475: 471: 468: ≡  467: 463: 459: 455: 451: 446: 442: 440: 436: 432: 429: ≡  428: 424: 420: 416: 411: 403: 401: 399: 395: 391: 387: 379: 377: 375: 371: 370:by definition 367: 359: 357: 350: 343: 338: 334: 330: 327: 323: 319: 314: 310: 306: 303: 299: 218: 217: 215: 209: 205: 198: 193: 189: 182: 178: 174: 170: 163: 160: ∃ 156: 153: ∃ 151: 147: 140: 137: ∀ 133: 127: 108: 104: 100: 99: 98: 95: 89: 87: 85: 84:with equality 81: 77: 72: 70: 66: 61: 59: 53: 50: 48: 45:We work with 40: 38: 36: 31: 27: 24:The proof of 18: 8295:Proof theory 8280:Model theory 8205: 8201: 8188: 8157: 7970: 7960: 7956: 7902: 7029: 7014: 7007: 7000: 6994: 6990: 6986: 6978: 6974: 6968: 6964: 6960: 6952: 6948: 6942: 6938: 6934: 6926: 6922: 6916: 6912: 6908: 6900: 6896: 6892: 6887: 6883: 6879: 6872: 6865: 6860: 6856: 6854: 6845:there is a D 6837: 6833: 6828: 6824: 6820: 6813: 6805: 6801: 6794: 6789: 6785: 6781: 6777: 6771: 6767: 6760: 6753: 6746: 6744: 6739: 6735: 6730: 6726: 6719: 6714: 6710: 6703: 6698: 6694: 6692: 6534: 6344: 6312: 6254: 6144: 6052: 5970:) affecting 5834: 5801:, such that 5717: 5713: 5682: 5653: 5648: 5359: 4857: 4853: 4852: 4814: 4813:: For every 4810: 4809: 4477: 3987:as follows: 3976: 3974: 3824: 3820: 3818: 3696: 3691: 3664: 3660: 3659:replaced by 3656: 3652: 3610: 3341: 3172: 3143: 2984: 2960: 2938: 2905:and we have 2904: 2720: 2670: 2666: 2662: 2658: 2654: 2598: 2412: 2258: 2254: 2202: 2173: 1990: 1986: 1982: 1978: 1974: 1970: 1966: 1964: 1832: 1828: 1827:denote here 1824: 1820: 1816: 1812: 1768: 1744: 1742: 1651: 1647: 1646: 1640: 1457: 1453: 1449: 1445: 1441: 1437: 1433: 1297: 1293: 1289: 1282: 1278: 1274: 1270: 1266: 1262: 1261: 1192: 1190: 922: 918: 916: 723: 719: 715: 711: 707: 703: 699: 695: 691: 687: 683: 679: 675: 673: 668: 664: 660: 656: 591: 587: 583: 579: 520: 519:are free in 515: 511: 504: 500: 498: 493: 489: 485: 481: 477: 473: 469: 465: 461: 457: 449: 447: 443: 434: 430: 426: 422: 418: 414: 409: 407: 397: 393: 389: 385: 383: 373: 369: 365: 363: 354: 341: 336: 332: 325: 321: 317: 312: 308: 298:truth values 207: 203: 196: 191: 187: 180: 176: 172: 168: 161: 154: 149: 145: 138: 131: 96: 93: 83: 79: 75: 73: 62: 54: 51: 44: 23: 8260:Kurt Gödel. 6734:) for some 5651:is proven. 4668:. Then put 2663:furthermore 478:normal form 462:normal form 454:prenex form 107:quantifiers 103:prenex form 41:Assumptions 8269:Categories 8249:Kurt Gödel 8222:56.0046.04 8178:References 8164:well-order 7021:Extensions 6921:there are 6055:for which 4860:; we have 1296:of degree 1281:of degree 1273:of degree 726:) we form 694:unused in 523:, we form 464:such that 259:...∃ 238:...∀ 30:Kurt Gödel 8230:123343522 8123:… 8102:… 8081:… 7981:φ 7940:… 7914:… 7881:φ 7859:∧ 7819:… 7800:≡ 7784:… 7762:→ 7721:∧ 7718:⋯ 7715:∧ 7658:… 7632:… 7619:∀ 7595:∧ 7592:⋯ 7589:∧ 7549:… 7530:≡ 7514:… 7492:→ 7451:∧ 7448:⋯ 7445:∧ 7388:… 7362:… 7349:∀ 7325:∧ 7277:→ 7250:→ 7205:∀ 7199:∧ 7153:→ 7126:→ 7081:∀ 7075:∧ 7045:∀ 6832:s within 6596:… 6575:φ 6559:… 6546:∃ 6473:… 6450:Ψ 6417:… 6384:Ψ 6098:− 5616:… 5577:… 5561:φ 5539:… 5526:∃ 5520:≡ 5498:… 5447:… 5419:φ 5397:… 5384:∃ 5378:≡ 5345:∧ 5337:− 5294:− 5264:… 5237:∀ 5201:… 5163:… 5135:φ 5119:… 5106:∃ 5075:… 5050:∀ 5044:∧ 5036:− 5025:⇐ 4990:… 4970:− 4956:∃ 4930:− 4916:… 4903:∀ 4897:∧ 4889:− 4878:⇐ 4828:→ 4825:φ 4779:∧ 4776:⋯ 4773:∧ 4760:∧ 4722:… 4709:∃ 4634:… 4614:− 4580:− 4541:… 4513:φ 4445:… 4394:… 4372:Σ 4307:precedes 4282:… 4236:… 4214:Σ 4194:… 4172:Σ 4138:… 4116:Σ 4096:… 4074:Σ 4040:… 4008:… 3944:… 3918:… 3902:φ 3886:… 3873:∃ 3854:… 3841:∀ 3795:Ψ 3753:∣ 3738:ψ 3720:∃ 3708:∀ 3678:φ 3675:¬ 3639:∧ 3619:∧ 3590:ψ 3572:∃ 3560:∀ 3554:→ 3551:ψ 3533:∃ 3521:∀ 3506:∀ 3494:∀ 3488:∧ 3463:∣ 3448:ψ 3430:∃ 3418:∀ 3401:∃ 3384:∀ 3375:¬ 3352:Φ 3349:¬ 3327:ψ 3309:∃ 3297:∀ 3252:∣ 3237:ψ 3219:∃ 3207:∀ 3184:Φ 3181:¬ 3156:Φ 3153:¬ 3130:Φ 3127:¬ 3107:Φ 3104:¬ 3084:Φ 3064:Ψ 3044:φ 3024:φ 3021:→ 3018:Φ 3015:∧ 3012:Φ 3009:≡ 3002:Φ 2998:≡ 2995:Ψ 2971:Ψ 2947:Ψ 2924:Ψ 2921:≡ 2914:Φ 2887:ψ 2884:→ 2860:∧ 2814:∃ 2797:∃ 2785:∀ 2773:∀ 2761:∀ 2744:∀ 2735:Ψ 2700:ρ 2696:∧ 2693:ρ 2637:ρ 2619:∧ 2616:ρ 2581:ψ 2578:→ 2539:∃ 2527:∀ 2515:∀ 2503:∀ 2497:∧ 2455:∃ 2438:∀ 2425:Φ 2395:ψ 2392:→ 2353:∃ 2341:∀ 2335:≡ 2329:ψ 2311:∃ 2299:∀ 2293:→ 2226:∃ 2214:∀ 2188:φ 2185:→ 2182:Φ 2174:Clearly, 2156:ψ 2138:∃ 2126:∀ 2120:→ 2090:∀ 2078:∀ 2072:∧ 2030:∃ 2013:∀ 2004:Φ 1940:… 1900:∀ 1897:⋯ 1884:∀ 1871:∀ 1845:∀ 1799:φ 1779:ψ 1755:φ 1728:ψ 1710:∃ 1698:∀ 1686:∃ 1674:∀ 1665:φ 1624:ψ 1621:→ 1592:∧ 1536:∃ 1524:∃ 1512:∀ 1500:∀ 1488:∀ 1471:∀ 1420:φ 1400:ψ 1371:ψ 1353:∃ 1341:∀ 1329:∃ 1317:∀ 1308:φ 1247:φ 1223:φ 1203:φ 1173:Φ 1147:∃ 1144:⋯ 1128:− 1112:∃ 1096:− 1080:∀ 1077:⋯ 1061:− 1045:∀ 1039:⋯ 1016:∃ 1013:⋯ 987:∃ 961:∀ 958:⋯ 945:∀ 936:φ 897:ψ 891:φ 856:¬ 853:∨ 832:∃ 826:∀ 788:¬ 785:∨ 767:∧ 764:Φ 755:∃ 740:∀ 734:ψ 643:φ 640:¬ 627:∀ 624:⋯ 611:∀ 605:ψ 602:¬ 566:φ 553:∃ 550:⋯ 537:∃ 531:ψ 490:Theorem 2 476:being in 410:Theorem 2 398:Theorem 1 394:Theorem 2 390:Theorem 2 386:Theorem 1 224:= ∀ 28:given by 8198:Gödel, K 8187:(1929). 8185:Gödel, K 7884:′ 6255:n > k 6082:through 4363:. [Here 3771:′ 3760:′ 3481:′ 3470:′ 3408:′ 3391:′ 3270:′ 3259:′ 3005:′ 2917:′ 2853:′ 2842:′ 2804:′ 2751:′ 2719:, where 2703:′ 2653:, where 2640:′ 2629:′ 2490:′ 2479:′ 2462:′ 2445:′ 2428:′ 2065:′ 2054:′ 2037:′ 2020:′ 1965:Let now 1602:′ 1585:′ 1574:′ 1563:′ 1543:′ 1478:′ 1444:′( 1383:, where 818:. Since 669:sentence 667:to be a 5654:Now if 4261:, and 1290:Comment 659:, thus 590:and if 400:holds. 266:φ( 252:∃ 245:∃ 231:∀ 130:∀ 123:∀ 119:∀ 115:∃ 111:∀ 67:or the 8228:  8220:  3981:tuples 1922:where 1829:tuples 1743:where 1648:Proof. 1294:φ 1265:. Let 1193:degree 720:matrix 706:.. If 676:prefix 435:φ 374:φ 366:φ 344:holds. 177:φ 8275:Logic 8251:"—by 8226:S2CID 7903:Here 6745:Take 6702:as Φ( 5649:Lemma 4854:Proof 4811:Lemma 4163:, or 3821:Lemma 3692:Lemma 1263:Lemma 578:. If 6172:and 5285:< 4695:as 4112:< 4024:< 3663:and 3655:and 2939:Now 2671:(S') 2659:(S') 2657:and 1989:and 1977:and 1969:and 1833:e.g. 1823:and 712:(P)Φ 702:and 423:i.e. 113:and 8247:: " 8218:JFM 8210:doi 6985:... 6959:... 6933:... 6907:... 6766:... 6725:... 6709:... 6532:). 5357:φ. 4505:as 4359:in 3983:of 2936:. 2721:(T) 2667:(S) 2655:(S) 2257:or 1745:(P) 1438:Q' 1195:of 678:of 510:... 460:in 425:, ( 384:If 287:... 273:... 8271:: 8224:. 8216:. 8206:37 7961:Eq 7957:Eq 7017:. 7006:, 6871:, 6800:, 6774:+1 5832:. 4850:. 4817:, 4475:. 3694:. 3665:y' 3661:x' 3339:. 3170:) 1971:y' 1967:x' 1819:, 1815:, 1811:. 710:= 372:"¬ 294:) 280:, 195:, 86:. 71:. 60:. 8255:. 8232:. 8212:: 8136:k 8131:k 8127:B 8118:k 8113:1 8109:B 8105:, 8099:, 8094:1 8089:k 8085:B 8076:1 8071:1 8067:B 8044:k 8040:D 8017:i 8012:k 8008:B 7985:i 7943:m 7937:k 7917:Z 7911:A 7888:. 7838:] 7835:) 7832:) 7827:m 7823:y 7814:1 7810:y 7806:( 7803:Z 7797:) 7792:m 7788:x 7779:1 7775:x 7771:( 7768:Z 7765:( 7759:) 7756:) 7751:m 7747:y 7743:, 7738:m 7734:x 7730:( 7727:q 7724:E 7712:) 7707:1 7703:y 7699:, 7694:1 7690:x 7686:( 7683:q 7680:E 7677:( 7674:[ 7671:) 7666:m 7662:x 7653:1 7649:y 7645:, 7640:m 7636:x 7627:1 7623:x 7616:( 7568:] 7565:) 7562:) 7557:k 7553:y 7544:1 7540:y 7536:( 7533:A 7527:) 7522:k 7518:x 7509:1 7505:x 7501:( 7498:A 7495:( 7489:) 7486:) 7481:k 7477:y 7473:, 7468:k 7464:x 7460:( 7457:q 7454:E 7442:) 7437:1 7433:y 7429:, 7424:1 7420:x 7416:( 7413:q 7410:E 7407:( 7404:[ 7401:) 7396:k 7392:x 7383:1 7379:y 7375:, 7370:k 7366:x 7357:1 7353:x 7346:( 7304:] 7301:) 7298:) 7295:y 7292:, 7289:z 7286:( 7283:q 7280:E 7274:) 7271:x 7268:, 7265:z 7262:( 7259:q 7256:E 7253:( 7247:) 7244:y 7241:, 7238:x 7235:( 7232:q 7229:E 7226:[ 7223:) 7220:z 7217:, 7214:y 7211:, 7208:x 7202:( 7180:] 7177:) 7174:) 7171:z 7168:, 7165:y 7162:( 7159:q 7156:E 7150:) 7147:z 7144:, 7141:x 7138:( 7135:q 7132:E 7129:( 7123:) 7120:y 7117:, 7114:x 7111:( 7108:q 7105:E 7102:[ 7099:) 7096:z 7093:, 7090:y 7087:, 7084:x 7078:( 7072:) 7069:x 7066:, 7063:x 7060:( 7057:q 7054:E 7051:) 7048:x 7042:( 7015:φ 7011:2 7008:z 7004:1 7001:z 6995:m 6991:q 6987:z 6982:1 6979:q 6975:z 6973:, 6969:k 6965:p 6961:z 6956:1 6953:p 6949:z 6943:m 6939:q 6935:z 6930:1 6927:q 6923:z 6917:k 6913:p 6909:z 6904:1 6901:p 6897:z 6893:k 6888:j 6884:B 6880:k 6876:2 6873:z 6869:1 6866:z 6861:n 6857:D 6849:i 6847:n 6843:i 6838:n 6834:D 6829:j 6825:B 6821:k 6817:1 6814:B 6809:1 6806:n 6802:D 6798:1 6795:n 6790:j 6786:B 6782:j 6778:k 6772:m 6768:z 6764:3 6761:z 6759:, 6757:2 6754:z 6750:1 6747:B 6740:y 6736:x 6731:m 6727:y 6723:1 6720:y 6718:, 6715:k 6711:x 6707:1 6704:x 6699:i 6695:B 6671:n 6667:a 6646:) 6641:m 6637:y 6633:. 6630:. 6627:. 6622:1 6618:y 6614:, 6609:n 6604:k 6600:a 6591:n 6586:1 6582:a 6578:( 6572:) 6567:m 6563:y 6554:1 6550:y 6543:( 6518:k 6514:D 6493:) 6486:i 6482:u 6477:z 6466:1 6462:u 6457:z 6453:( 6430:) 6425:i 6421:u 6412:1 6408:u 6404:( 6358:k 6354:D 6328:n 6324:D 6313:n 6297:k 6293:D 6270:h 6266:E 6239:n 6235:D 6212:k 6208:B 6185:k 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5068:n 5063:1 5059:a 5054:z 5047:( 5039:1 5033:n 5029:D 5020:n 5016:B 5012:) 5007:1 5004:+ 5001:m 4998:n 4994:z 4985:2 4982:+ 4979:m 4976:) 4973:1 4967:n 4964:( 4960:z 4953:( 4950:) 4945:1 4942:+ 4939:m 4936:) 4933:1 4927:n 4924:( 4920:z 4911:1 4907:z 4900:( 4892:1 4886:n 4882:D 4873:n 4869:D 4858:n 4836:n 4832:D 4815:n 4795:. 4792:) 4787:n 4783:B 4768:2 4764:B 4755:1 4751:B 4747:( 4744:) 4739:1 4736:+ 4733:m 4730:n 4726:z 4717:1 4713:z 4706:( 4681:n 4677:D 4656:) 4651:1 4648:+ 4645:m 4642:n 4638:z 4629:3 4626:+ 4623:m 4620:) 4617:1 4611:n 4608:( 4604:z 4600:, 4595:2 4592:+ 4589:m 4586:) 4583:1 4577:n 4574:( 4570:z 4566:, 4559:n 4554:k 4550:a 4545:z 4534:n 4529:1 4525:a 4520:z 4516:( 4491:n 4487:B 4463:) 4458:n 4453:k 4449:a 4440:n 4435:1 4431:a 4427:( 4407:) 4402:k 4398:x 4389:1 4385:x 4381:( 4376:k 4347:) 4342:k 4338:y 4334:. 4331:. 4328:. 4323:1 4319:y 4315:( 4295:) 4290:k 4286:x 4277:1 4273:x 4269:( 4249:) 4244:k 4240:y 4231:1 4227:y 4223:( 4218:k 4210:= 4207:) 4202:k 4198:x 4189:1 4185:x 4181:( 4176:k 4151:) 4146:k 4142:y 4133:1 4129:y 4125:( 4120:k 4109:) 4104:k 4100:x 4091:1 4087:x 4083:( 4078:k 4053:) 4048:k 4044:y 4035:1 4031:y 4027:( 4021:) 4016:k 4012:x 4003:1 3999:x 3995:( 3979:- 3977:k 3960:. 3957:) 3952:m 3948:y 3939:1 3935:y 3931:, 3926:k 3922:x 3913:1 3909:x 3905:( 3899:) 3894:m 3890:y 3881:1 3877:y 3870:( 3867:) 3862:k 3858:x 3849:1 3845:x 3838:( 3825:R 3775:) 3768:y 3764:, 3757:x 3750:y 3747:, 3744:x 3741:( 3735:) 3732:P 3729:( 3726:) 3723:v 3717:( 3714:) 3711:u 3705:( 3657:y 3653:x 3596:) 3593:) 3587:) 3584:P 3581:( 3578:) 3575:v 3569:( 3566:) 3563:u 3557:( 3548:) 3545:P 3542:( 3539:) 3536:v 3530:( 3527:) 3524:u 3518:( 3515:( 3512:) 3509:y 3503:( 3500:) 3497:x 3491:( 3485:) 3478:y 3474:, 3467:x 3460:y 3457:, 3454:x 3451:( 3445:) 3442:P 3439:( 3436:) 3433:v 3427:( 3424:) 3421:u 3415:( 3412:) 3405:y 3398:( 3395:) 3388:x 3381:( 3378:( 3324:) 3321:P 3318:( 3315:) 3312:v 3306:( 3303:) 3300:u 3294:( 3274:) 3267:y 3263:, 3256:x 3249:y 3246:, 3243:x 3240:( 3234:) 3231:P 3228:( 3225:) 3222:v 3216:( 3213:) 3210:u 3204:( 2985:M 2961:k 2890:) 2881:) 2878:y 2875:, 2872:x 2869:( 2866:Q 2863:( 2857:) 2850:y 2846:, 2839:x 2835:( 2832:Q 2829:) 2826:P 2823:( 2820:) 2817:v 2811:( 2808:) 2801:y 2794:( 2791:) 2788:u 2782:( 2779:) 2776:y 2770:( 2767:) 2764:x 2758:( 2755:) 2748:x 2741:( 2738:= 2707:) 2690:( 2687:) 2684:T 2681:( 2633:) 2626:S 2622:( 2613:) 2610:S 2607:( 2584:) 2575:) 2572:y 2569:, 2566:x 2563:( 2560:Q 2557:( 2554:) 2551:P 2548:( 2545:) 2542:v 2536:( 2533:) 2530:u 2524:( 2521:) 2518:y 2512:( 2509:) 2506:x 2500:( 2494:) 2487:y 2483:, 2476:x 2472:( 2469:Q 2466:) 2459:y 2452:( 2449:) 2442:x 2435:( 2432:= 2398:) 2389:) 2386:y 2383:, 2380:x 2377:( 2374:Q 2371:( 2368:) 2365:P 2362:( 2359:) 2356:v 2350:( 2347:) 2344:u 2338:( 2332:) 2326:) 2323:P 2320:( 2317:) 2314:v 2308:( 2305:) 2302:u 2296:( 2290:) 2287:y 2284:, 2281:x 2278:( 2275:Q 2272:( 2259:y 2255:x 2241:) 2238:P 2235:( 2232:) 2229:v 2223:( 2220:) 2217:u 2211:( 2159:) 2153:) 2150:P 2147:( 2144:) 2141:v 2135:( 2132:) 2129:u 2123:( 2117:) 2114:y 2111:, 2108:x 2105:( 2102:Q 2099:( 2096:) 2093:y 2087:( 2084:) 2081:x 2075:( 2069:) 2062:y 2058:, 2051:x 2047:( 2044:Q 2041:) 2034:y 2027:( 2024:) 2017:x 2010:( 2007:= 1991:y 1987:x 1983:Q 1979:y 1975:x 1948:n 1944:x 1935:1 1931:x 1908:n 1904:x 1892:2 1888:x 1879:1 1875:x 1851:) 1848:x 1842:( 1825:v 1821:u 1817:y 1813:x 1769:k 1725:) 1722:P 1719:( 1716:) 1713:v 1707:( 1704:) 1701:u 1695:( 1692:) 1689:y 1683:( 1680:) 1677:x 1671:( 1668:= 1652:k 1627:) 1618:) 1615:y 1612:, 1609:x 1606:( 1599:Q 1595:( 1589:) 1582:y 1578:, 1571:x 1567:( 1560:Q 1556:) 1553:P 1550:( 1547:) 1540:y 1533:( 1530:) 1527:v 1521:( 1518:) 1515:u 1509:( 1506:) 1503:y 1497:( 1494:) 1491:x 1485:( 1482:) 1475:x 1468:( 1458:k 1454:y 1450:y 1448:, 1446:x 1442:Q 1434:k 1397:) 1394:P 1391:( 1368:) 1365:P 1362:( 1359:) 1356:v 1350:( 1347:) 1344:u 1338:( 1335:) 1332:y 1326:( 1323:) 1320:x 1314:( 1311:= 1298:k 1283:k 1279:R 1275:k 1271:R 1267:k 1176:) 1170:( 1167:) 1160:n 1156:k 1151:x 1139:1 1136:+ 1131:1 1125:n 1121:k 1116:x 1109:( 1106:) 1099:1 1093:n 1089:k 1084:x 1072:1 1069:+ 1064:2 1058:n 1054:k 1049:x 1042:( 1036:) 1029:2 1025:k 1020:x 1008:1 1005:+ 1000:1 996:k 991:x 984:( 981:) 974:1 970:k 965:x 953:1 949:x 942:( 939:= 923:R 919:R 894:= 871:) 868:) 865:z 862:( 859:F 850:) 847:y 844:( 841:F 838:( 835:z 829:y 806:) 803:] 800:) 797:z 794:( 791:F 782:) 779:y 776:( 773:F 770:[ 761:( 758:z 752:) 749:P 746:( 743:y 737:= 724:φ 716:φ 708:φ 704:z 700:y 696:φ 692:F 688:φ 684:φ 680:φ 665:φ 661:φ 657:φ 635:n 631:x 619:1 615:x 608:= 592:ψ 588:φ 584:M 580:ψ 561:n 557:x 545:1 541:x 534:= 521:φ 516:n 512:x 508:1 505:x 501:φ 494:φ 486:ψ 482:ψ 474:ψ 472:( 470:ψ 466:φ 458:ψ 450:φ 431:ψ 427:φ 419:C 415:C 364:" 342:φ 337:n 333:D 326:φ 322:B 318:n 316:( 313:n 309:D 291:m 289:y 284:1 282:y 277:k 275:x 270:1 268:x 263:m 261:y 256:2 254:y 249:1 247:y 242:k 240:x 235:2 233:x 228:1 226:x 222:B 211:) 208:m 204:y 200:1 197:y 192:k 188:x 184:1 181:x 179:( 173:m 169:y 165:2 162:y 158:1 155:y 150:k 146:x 142:2 139:x 135:1 132:x 125:. 109:(

Index


Gödel's completeness theorem
Kurt Gödel
mathematical logic
first-order predicate calculus
Hilbert-Ackermann proof system
normal form theorem
soundness theorem
prenex form
quantifiers
truth values
propositional logic
soundness theorem
prenex form
Löwenheim–Skolem theorem
well-formed formula
tuples
natural numbers
lexicographic order
propositional logic
natural numbers
Axiom of Choice
well-order
transfinite induction
Boolean prime ideal theorem
Gödel, K
Gödel, K
doi
10.1007/BF01696781
JFM

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