No syllogisms for the numerical syllogistic

Abstract. The numerical syllogistic is the extension of the traditional syllogistic with numerical quantifiers of the forms at least C and at most C. It is known that, for the traditional syllogistic, a finite collection of rules, similar in spirit to the classical syllogisms, constitutes a sound and complete proof-system. The question arises as to whether such a proof system exists for the numerical syllogistic. This paper answers that question in the negative: no finite collection of syllogism-like rules, broadly conceived, is sound and complete for the numerical syllogistic.

A Resolution Decision Procedure for Fluted Logic

Fluted logic is a fragment of first-order logic without function symbols in which the arguments of atomic subformulae form ordered sequences. A consequence of this restriction is that, whereas first-order logic is only semi-decidable, fluted logic is decidable. In this paper we present a sound, complete and terminating inference procedure for fluted logic. Our characterisation of fluted logic is in terms of a new class of socalled fluted clauses. We show that this class is decidable by an ordering refinement of first-order resolution and a new form of dynamic renaming, called separation

Natural logic for natural language

Abstract. For a cognitive account of reasoning it is useful to factor out the syntactic aspect — the aspect that has to do with pattern matching and simple substitution — from the rest. The calculus of monotonicity, alias the calculus of natural logic, does precisely this, for it is a calculus of appropriate substitutions at marked positions in syntactic structures. We first introduce the semantic and the syntactic sides of monotonicity reasoning or ‘natural logic’, and propose an improvement to the syntactic monotonicity calculus, in the form of an improved algorithm for monotonicity marking. Next, we focus on the role of monotonicity in syllogistic reasoning. In particular, we show how the syllogistic inference rules (for traditional syllogistics, but also for a broader class of quantifiers) can be decomposed in a monotonicity component, an argument swap component, and an existential import component. Finally, we connect the decomposition of syllogistics to the doctrine of distribution.