Recovering a Logic from Its Fragments by Meta-Fibring

Autor(es)

Coniglio, Marcelo Esteban

• Tipo de documento: Artigo Científico
• Fonte: LOGICA UNIVERSALIS; v. 1, n. 2, p. 40-pg., 2007-10-01.

Resumo

In this paper we address the question of recovering a logic system by combining two or more fragments of it. We show that, in general, by fibring two or more fragments of a given logic the resulting logic is weaker than the original one, because some meta-properties of the connectives are lost after the combination process. In order to overcome this problem, the categories Mcon and Seq of multiple-conclusion consequence relations and sequent calculi, respectively, are introduced. The main feature of these categories is the preservation, by morphisms, of meta-properties of the consequence relations, which allows, in several cases, to recover a logic by fibring of its fragments. The fibring in this categories is called meta-fibring. Several examples of well-known logics which can be recovered by meta-fibring its fragments (in opposition to fibring in the usual categories) are given. Finally, a general semantics for objects in Seq (and, in particular, for objects in Mcon) is proposed, obtaining a category of logic systems called Log. A general theorem of preservation of completeness by fibring in Log is also obtained. (AU)

• Processo FAPESP: 04/14107-2 - Logical consequence and combinations of logics: fundaments and efficient applications
• Beneficiário: Walter Alexandre Carnielli
• Modalidade de apoio: Auxílio à Pesquisa - Temático