Montague, Richard Merett (1930–71)

2018 ◽  
Author(s):  
Terence Parsons
Keyword(s):  
Set Theory ◽  
Recursion Theory ◽  
Order Logic ◽  
Higher Order Logic ◽  
Semantic Paradox ◽  
Deterministic Theory ◽  
Richard Montague ◽  
Axiomatic Set Theory ◽  
Special Case ◽  
Algebra Model

Richard Montague was a logician, philosopher and mathematician. His mathematical contributions include work in Boolean algebra, model theory, proof theory, recursion theory, axiomatic set theory and higher-order logic. He developed a modal logic in which necessity appears as a predicate of sentences, showing how analogues of the semantic paradoxes relate to this notion. Analogously, he (with David Kaplan) argued that a special case of the surprise examination paradox can also be seen as an epistemic version of semantic paradox. He made important contributions to the problem of formulating the notion of a ‘deterministic’ theory in science.

Resolution in type theory

1971 ◽  
Vol 36 (3) ◽  
pp. 414-432 ◽  
Author(s):  
Peter B. Andrews
Keyword(s):  
Set Theory ◽  
Type Theory ◽  
Higher Order ◽  
Order Logic ◽  
First Order Logic ◽  
Higher Order Logic ◽  
First Order ◽  
Different Types ◽  
Axiomatic Set Theory ◽  
Order Predicate Calculus

In [8] J. A. Robinson introduced a complete refutation procedure called resolution for first order predicate calculus. Resolution is based on ideas in Herbrand's Theorem, and provides a very convenient framework in which to search for a proof of a wff believed to be a theorem. Moreover, it has proved possible to formulate many refinements of resolution which are still complete but are more efficient, at least in many contexts. However, when efficiency is a prime consideration, the restriction to first order logic is unfortunate, since many statements of mathematics (and other disciplines) can be expressed more simply and naturally in higher order logic than in first order logic. Also, the fact that in higher order logic (as in many-sorted first order logic) there is an explicit syntactic distinction between expressions which denote different types of intuitive objects is of great value where matching is involved, since one is automatically prevented from trying to make certain inappropriate matches. (One may contrast this with the situation in which mathematical statements are expressed in the symbolism of axiomatic set theory.).

Higher‐order Logic Reconsidered

2009 ◽  
Author(s):  
Ignacio Jané
Keyword(s):  
Set Theory ◽  
Logical Consequence ◽  
Higher Order ◽  
Second Order ◽  
Order Logic ◽  
Higher Order Logic ◽  
Consequence Relation ◽  
Fourth Section ◽  
Second Order Logic

This article discusses canonical (i.e., full, or standard) second-order consequence and argues against it being a case of logical consequence. The discussion is divided into three parts. The first part comprises the first three sections. After stating the problem in Section 1, Sections 2 and 3 examine the role that the consequence relation is expected to play in axiomatic theories. This leads to put forward two requirements on logical consequence, which are called “formality” and “noninterference.” It is this last requirement that canonical second-order consequence violates, as the article sets out to substantiate. The fourth section argues that canonical second-order logic is inadequate for axiomatizing set theory, on the grounds that it codes a significant amount of set-theoretical content.

KURT GÖDEL’S FIRST STEPS IN LOGIC: FORMAL PROOFS IN ARITHMETIC AND SET THEORY THROUGH A SYSTEM OF NATURAL DEDUCTION

2018 ◽  
Vol 24 (3) ◽  
pp. 319-335
Author(s):  
JAN VON PLATO
Keyword(s):  
Linear System ◽  
Set Theory ◽  
Natural Deduction ◽  
Higher Order ◽  
Order Logic ◽  
Formal Proofs ◽  
Higher Order Logic ◽  
Order Arithmetic

AbstractWhat seem to be Kurt Gödel’s first notes on logic, an exercise notebook of 84 pages, contains formal proofs in higher-order arithmetic and set theory. The choice of these topics is clearly suggested by their inclusion in Hilbert and Ackermann’s logic book of 1928, the Grundzüge der theoretischen Logik. Such proofs are notoriously hard to construct within axiomatic logic. Gödel takes without further ado into use a linear system of natural deduction for the full language of higher-order logic, with formal derivations closer to one hundred steps in length and up to four nested temporary assumptions with their scope indicated by vertical intermittent lines.

scholarly journals WHAT RUSSELL SHOULD HAVE SAID TO BURALI–FORTI

2017 ◽  
Vol 10 (4) ◽  
pp. 682-718 ◽  
Author(s):  
SALVATORE FLORIO ◽  
GRAHAM LEACH-KROUSE
Keyword(s):  
Set Theory ◽  
Current Literature ◽  
Concept Formation ◽  
Ordinal Number ◽  
Higher Order ◽  
Order Logic ◽  
Higher Order Logic ◽  
Class Theory

AbstractThe paradox that appears under Burali–Forti’s name in many textbooks of set theory is a clever piece of reasoning leading to an unproblematic theorem. The theorem asserts that the ordinals do not form a set. For such a set would be–absurdly–an ordinal greater than any ordinal in the set of all ordinals. In this article, we argue that the paradox of Burali–Forti is first and foremost a problem about concept formation by abstraction, not about sets. We contend, furthermore, that some hundred years after its discovery the paradox is still without any fully satisfactory resolution. A survey of the current literature reveals one key assumption of the paradox that has gone unquestioned, namely the assumption that ordinals are objects. Taking the lead from Russell’s no class theory, we interpret talk of ordinals as an efficient way of conveying higher-order logical truths. The resulting theory of ordinals is formally adequate to standard intuitions about ordinals, expresses a conception of ordinal number capable of resolving Burali–Forti’s paradox, and offers a novel contribution to the longstanding program of reducing mathematics to higher-order logic.

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