O objetivo deste trabalho é apresentar uma definição materialmente adequada de verdade, no sentido de Tarski, para uma classe de linguagens formais capaz de expressar as proposições categóricas da lógica aristotélica.The aim of this paper is to put forward a materially adequate definition of truth, in Tarski's sense, for a class of formal languages that would be able to represent the categorical propositions of Aristotelian logic.

Resumo: Apresentamos uma abordagem geral da demonstração de completude de cálculos lógicos abstratos por meio da noção de valoração e de um resultado devido a A. Lindenbaum.: We present a general approach to the proof the completeness of abstract logical calculi through the notion of valuation and of a result due to A. Lindenbaum.

Infinitary languages are used to prove that any strong isomorphism of substructures of isomorphic structures can be extended to an isomorphism of the structures. If the structures are models of a theory that has quantifier elimination, any isomorphism of substructures is strong. This theorem is a partial generalization of Steinitz’s theorem for algebraically closed fields and has as special case the analogous theorem for differentially closed fields. In this note, we announce results which will be proved elsewhere.