P. C. Gilmore. A program for the production from axioms, of proofs for theorems derivable within the first order predicate calculus. English, with English, French, German, Russian, and Spanish summaries. Information processing, Proceedings of the International Conference on Information Processing, Unesco, Paris 15–20 June 1959, Unesco, Paris, R. Oldenbourg, Munich, Butterworths, London, 1960, pp. 265–273. - J. Porte, P. C. Gilmore, Dag H. Prawitz, Håkon Prawitz, and Neri Voghera. Discussion. Information processing, Proceedings of the International Conference on Information Processing, Unesco, Paris 15–20 June 1959, Unesco, Paris, R. Oldenbourg, Munich, Butterworths, London, 1960, p. 273. - P. C. Gilmore. A proof method for quantification theory: Its justification and realization. IBM journal of research and development, vol. 4 (1960), pp. 28–35.

1966 ◽  
Vol 31 (1) ◽  
pp. 124-125
Author(s):  
J. A. Robinson
1954 ◽  
Vol 19 (3) ◽  
pp. 177-179 ◽  
Author(s):  
W. V. Quine

Quantification theory, or the first-order predicate calculus, is ordinarily so formulated as to provide as theorems all and only those formulas which come out true under all interpretations in all non-empty domains. There are two strong reasons for thus leaving aside the empty domain.(i) Where D is any non-empty domain, any quantificational formula which comes out true under all interpretations in all domains larger than D will come out true also under all interpretations in D. (Cf. [4], p. 92.) Thus, though any small domain has a certain triviality, all but one of them, the empty domain, can be included without cost. To include the empty one, on the other hand, would mean surrendering some formulas which are valid everywhere else and thus generally useful.(ii) An easy supplementary test enables us anyway, when we please, to decide whether a formula holds for the empty domain. We have only to mark the universal quantifications as true and the existential ones as false, and apply truth-table considerations.Incidentally, the existence of that supplementary test shows that there is no difficulty in framing an inclusive quantification theory (i.e., inclusive of the empty domain) if we so desire. A proof in this theory can be made to consist simply of a proof in the exclusive (or usual) theory followed by a check by the method of (ii). We may, however, be curious to see a more direct or autonomous formulation: one which does not consist, like the above, of the exclusive theory plus a rule of expurgation. And, in fact, such formulations have of late been forthcoming: Mostowski [5], Hailperin [3], and, as part of a broader context, Church [2]. I shall not presuppose acquaintance with these papers, except in my final paragraph (and then only with [3]).


1976 ◽  
Vol 41 (1) ◽  
pp. 45-49
Author(s):  
Charles E. Hughes

AbstractA new reduction class is presented for the satisfiability problem for well-formed formulas of the first-order predicate calculus. The members of this class are closed prenex formulas of the form ∀x∀yC. The matrix C is in conjunctive normal form and has no disjuncts with more than three literals, in fact all but one conjunct is unary. Furthermore C contains but one predicate symbol, that being unary, and one function symbol which symbol is binary.


1970 ◽  
Vol 38 ◽  
pp. 145-152
Author(s):  
Akira Nakamura

The purpose of this paper is to present a propositional calculus whose decision problem is recursively unsolvable. The paper is based on the following ideas: (1) Using Löwenheim-Skolem’s Theorem and Surányi’s Reduction Theorem, we will construct an infinitely many-valued propositional calculus corresponding to the first-order predicate calculus.(2) It is well known that the decision problem of the first-order predicate calculus is recursively unsolvable.(3) Thus it will be shown that the decision problem of the infinitely many-valued propositional calculus is recursively unsolvable.


1969 ◽  
Vol 34 (2) ◽  
pp. 226-252 ◽  
Author(s):  
Jon Barwise

In recent years much effort has gone into the study of languages which strengthen the classical first-order predicate calculus in various ways. This effort has been motivated by the desire to find a language which is(I) strong enough to express interesting properties not expressible by the classical language, but(II) still simple enough to yield interesting general results. Languages investigated include second-order logic, weak second-order logic, ω-logic, languages with generalized quantifiers, and infinitary logic.


1955 ◽  
Vol 20 (2) ◽  
pp. 115-118 ◽  
Author(s):  
M. H. Löb

If Σ is any standard formal system adequate for recursive number theory, a formula (having a certain integer q as its Gödel number) can be constructed which expresses the proposition that the formula with Gödel number q is provable in Σ. Is this formula provable or independent in Σ? [2].One approach to this problem is discussed by Kreisel in [4]. However, he still leaves open the question whether the formula (Ex)(x, a), with Gödel-number a, is provable or not. Here (x, y) is the number-theoretic predicate which expresses the proposition that x is the number of a formal proof of the formula with Gödel-number y.In this note we present a solution of the previous problem with respect to the system Zμ [3] pp. 289–294, and, more generally, with respect to any system whose set of theorems is closed under the rules of inference of the first order predicate calculus, and satisfies the subsequent five conditions, and in which the function (k, l) used below is definable.The notation and terminology is in the main that of [3] pp. 306–326, viz. if is a formula of Zμ containing no free variables, whose Gödel number is a, then ({}) stands for (Ex)(x, a) (read: the formula with Gödel number a is provable in Zμ); if is a formula of Zμ containing a free variable, y say, ({}) stands for (Ex)(x, g(y)}, where g(y) is a recursive function such that for an arbitrary numeral the value of g() is the Gödel number of the formula obtained from by substituting for y in throughout. We shall, however, depart trivially from [3] in writing (), where is an arbitrary numeral, for (Ex){x, ).


1976 ◽  
Vol 41 (4) ◽  
pp. 730-746
Author(s):  
Kenneth Slonneger

This paper is concerned with the proof theoretic development of certain infinite languages. These languages contain the usual infinite conjunctions and disjunctions, but in addition to homogeneous quantifiers such as ∀x0x1x2 … and ∃y0y1y2 …, we shall investigate particular subclasses of the dependent quantifiers described by Henkin [1]. The dependent quantifiers of Henkin can be thought of as partially ordered quantifiers defined by a function from one set to the power set of another set. This function assigns to each existentially bound variable, the set of universally bound variables on which it depends.The natural extension of Gentzen's first order predicate calculus to an infinite language with homogeneous quantifiers results in a system that is both valid and complete, and in which a cut elimination theorem can be proved [2]. The problem then arises of devising, if possible, a logical system dealing with general dependent quantifiers that is valid and complete. In this paper a system is presented that is valid and complete for an infinite language with homogeneous quantifiers and dependent quantifiers that are anti-well-ordered, for example, … ∀x2∃y2∀x1∃y1∀x0∃y0.Certain notational conventions will be employed in this paper. Greek letters will be used for ordinal numbers. The ordinal ω is the set of all natural numbers, and 2ω is the set of all ω -sequences of elements of 2 = {0,1}. The power set of S is denoted by P(S). μα[A(α)] stands for the smallest ordinal α such that A (α) holds.


1958 ◽  
Vol 23 (4) ◽  
pp. 417-419 ◽  
Author(s):  
R. L. Goodstein

Mr. L. J. Cohen's interesting example of a logical truth of indirect discourse appears to be capable of a simple formalisation and proof in a variant of first order predicate calculus. His example has the form:If A says that anything which B says is false, and B says that something which A says is true, then something which A says is false and something which B says is true.Let ‘A says x’ be formalised by ‘A(x)’ and let assertions of truth and falsehood be formalised as in the following table.We treat both variables x and predicates A (x) as sentences and add to the familiar axioms and inference rules of predicate logic a rule permitting the inference of A(p) from (x)A(x), where p is a closed sentence.We have to prove that from


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