A first order logic for partial functions

Author(s):  
Francisca Lucio-Carrasco ◽  
Antonio Gavilanes-Franco
1988 ◽  
Vol 53 (3) ◽  
pp. 834-839 ◽  
Author(s):  
H. Andréka ◽  
W. Craig ◽  
I. Németi

Ordinary equational logic is a connective-free fragment of first-order logic which is concerned with total functions under the relation of ordinary equality. In [AN] (see also [AN1]) and in [Cr] it has been extended in two equivalent ways into a near-equational system of logic for partial functions. The extension given in [Cr] deals with partial functions under two relationships: a relationship of existence-dependent existence and one of existence-dependent Kleene equality. For the language that involves both relationships a set of rules was given that is complete. Those rules in the set that involve only existence-dependent existence turned out to be complete for the sublanguage that involves this relationship only. In the present paper we give a set of rules that is complete for the other sublanguage, namely the language of partial functions under existence-dependent Kleene equality.This language lacks a certain, often needed, power of expressing existence and fails, in particular, to be an extension of the language that underlies ordinary equational logic. That it possesses a fairly simple complete set of rules is therefore perhaps more of theoretical than of practical interest. The present paper is thus intended to serve as a supplement to [Cr] and, less directly, to [AN]. The subject is further rounded out, and some contrast is provided, by [Rob]. The systems of logic treated there are based on the weaker language in which partial functions are considered under the more basic relation of Kleene equality.


1996 ◽  
Vol 61 (3) ◽  
pp. 843-872 ◽  
Author(s):  
Silvio Ghilardi ◽  
Giancarlo Meloni

AbstractIn this paper we study the logic of relational and partial variable sets, seen as a generalization of set-valued presheaves, allowing transition functions to be arbitrary relations or arbitrary partial functions. We find that such a logic is the usual intuitionistic and co-intuitionistic first order logic without Beck and Frobenius conditions relative to quantifiers along arbitrary terms. The important case of partial variable sets is axiomatizable by means of the substitutivity schema for equality. Furthermore, completeness, incompleteness and independence results are obtained for different kinds of Beck and Frobenius conditions.


1990 ◽  
Vol 74 (1) ◽  
pp. 37-69 ◽  
Author(s):  
Antonio Gavilanes-Franco ◽  
Francisca Lucio-Carrasco

2013 ◽  
Vol 13 (4-5) ◽  
pp. 691-704 ◽  
Author(s):  
JOACHIM JANSEN ◽  
ALBERT JORISSEN ◽  
GERDA JANSSENS

AbstractFO(·)IDP3extends first-order logic with inductive definitions, partial functions, types and aggregates. Its model generator IDP3 first grounds the theory and then uses search to find the models. The grounder uses Lifted Unit Propagation (LUP) to reduce the size of the groundings of problem specifications in IDP3. LUP is in general very effective, but performs poorly on definitions of predicates whose two-valued interpretation can be computed from data in the input structure. To solve this problem, a preprocessing step is introduced that converts such definitions to Prolog code and usesXSBProlog to compute their interpretation. The interpretation of these predicates is then added to the input structure, their definitions are removed from the theory and further processing is done by the standard IDP3 system. Experimental results show the effectiveness of our method.


Author(s):  
Liliana María Favre

In this chapter we examine the relation between NEREUS and formal specification using CASL (Common Algebraic Specification Language) as a common algebraic language (Bidoit & Mosses, 2004). CASL is an expressive and simple language based on a critical selection of known constructs such as subsorts, partial functions, first-order logic, and structured and architectural specifications. A basic specification declares sorts, subsorts, operations and predicates, and gives axioms and constraints. Specifications are structured by means of specification building operators for renaming, extension and combining. Architectural specifications impose structure on implementations, whereas structured specifications only structure the text of specifications. CASL allows loose, free and generated specifications. The models of a loose specification include all those where the declared functions have the specified properties, without any restrictions on the set of values corresponding to the various sorts. In models of a generated specification, in contrast, it is required that all values can be expressed by terms formed from the specified constructors, i.e. unreachable values are prohibited. In models of free specifications, it is required that values of terms are distinct except when their equality follows from the specified axioms: the possibility of unintended coincidence between their axioms is prohibited.


2009 ◽  
Vol 19 (12) ◽  
pp. 3091-3099 ◽  
Author(s):  
Gui-Hong XU ◽  
Jian ZHANG

Author(s):  
Tim Button ◽  
Sean Walsh

Chapters 6-12 are driven by questions about the ability to pin down mathematical entities and to articulate mathematical concepts. This chapter is driven by similar questions about the ability to pin down the semantic frameworks of language. It transpires that there are not just non-standard models, but non-standard ways of doing model theory itself. In more detail: whilst we normally outline a two-valued semantics which makes sentences True or False in a model, the inference rules for first-order logic are compatible with a four-valued semantics; or a semantics with countably many values; or what-have-you. The appropriate level of generality here is that of a Boolean-valued model, which we introduce. And the plurality of possible semantic values gives rise to perhaps the ‘deepest’ level of indeterminacy questions: How can humans pin down the semantic framework for their languages? We consider three different ways for inferentialists to respond to this question.


2020 ◽  
Author(s):  
Michał Walicki

Abstract Graph normal form, introduced earlier for propositional logic, is shown to be a normal form also for first-order logic. It allows to view syntax of theories as digraphs, while their semantics as kernels of these digraphs. Graphs are particularly well suited for studying circularity, and we provide some general means for verifying that circular or apparently circular extensions are conservative. Traditional syntactic means of ensuring conservativity, like definitional extensions or positive occurrences guaranteeing exsitence of fixed points, emerge as special cases.


1991 ◽  
Vol 15 (2) ◽  
pp. 123-138
Author(s):  
Joachim Biskup ◽  
Bernhard Convent

In this paper the relationship between dependency theory and first-order logic is explored in order to show how relational chase procedures (i.e., algorithms to decide inference problems for dependencies) can be interpreted as clever implementations of well known refutation procedures of first-order logic with resolution and paramodulation. On the one hand this alternative interpretation provides a deeper insight into the theoretical foundations of chase procedures, whereas on the other hand it makes available an already well established theory with a great amount of known results and techniques to be used for further investigations of the inference problem for dependencies. Our presentation is a detailed and careful elaboration of an idea formerly outlined by Grant and Jacobs which up to now seems to be disregarded by the database community although it definitely deserves more attention.


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