Cristina Sernadas

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TROLL is a language particularly suited for the early stages of information system development, when the universe of discourse must be described. In TROLL the descriptions of the static and dynamic aspects of entities are integrated into object descriptions. Sublanguages for data terms, for first-order and temporal assertions, and for processes, are used to(More)
Much attention has been given recently to the mechanism of fibring of logics, allowing free mixing of the connectives and using proof rules from both logics. Fibring seems to be a rather useful and general form of combination of logics that deserves detailed study. It is now well understood at the proof-theoretic level. However, the semantics of fibring is(More)
A completeness theorem is established for logics with congruence endowed with general semantics (in the style of general frames). As a corollary, completeness is shown to be preserved by fibring logics with congruence provided that congruence is retained in the resulting logic. The class of logics with equivalence is shown to be closed under fibring and to(More)
Fibring has been shown to be useful for combining logics endowed with truthfunctional semantics. However, the techniques used so far are unable to cope with fibring of logics endowed with non-truth-functional semantics as, for example, paraconsistent logics. The first main contribution of the paper is the development of a suitable abstract notion of logic,(More)
Fibring is recognized as one of the main mechanisms in combining logics, with great significance in the theory and applications of mathematical logic. However, an open challenge to fibring is posed by the collapsing problem: even when no symbols are shared, certain combinations of logics simply collapse to one of them, indicating that fibring imposes(More)
A formal semantics for the kernel constructs of an object-oriented specification language is presented. The formal counterparts of objects as the basic building blocks of information systems are given by theory presentations in a logic that has been developed to support the required objectoriented specification mechanisms. Attributes (structure) and events(More)
1 PROLEGOMENON TO FIBRING It is a task of philosophy to explain the sense in which contemporary science uses the label " logics " , specially through " logics in " (natural language, program verification, machine learning, knowledge representation, abduc-tive and inductive reasoning, etc.) as well as " logics for " (hybrid reasoning systems, ontology,(More)