Artículos con la etiqueta ‘lenguajes formales’

Logique mathématique et linguistique formelle

Por • 13 nov, 2013 • Category: Leyes

As the etymology of the word shows, logic is intimately related to language, as exemplified by the work of philosophers from Antiquity and from the Middle-Age. At the beginning of the XX century, the crisis of the foundations of mathematics invented mathematical logic and imposed logic as a language-based foundation for mathematics. How did the relations between logic and language evolved in this newly defined mathematical framework? After a survey of the history of the relation between logic and linguistics, traditionally focused on semantics, we focus on some present issues: 1) grammar as a deductive system 2) the transformation of the syntactic structure of a sentence to a logical formula representing its meaning 3) taking into account the context when interpreting words. This lecture shows that type theory provides a convenient framework both for natural language syntax and for the interpretation of any of tis level (words, sentences, discourse).

The Unary Fragments of Metric Interval Temporal Logic: Bounded versus Lower bound Constraints (Full Version)

Por • 17 may, 2013 • Category: Filosofía

We study two unary fragments of the well-known metric interval temporal logic MITL[U_I,S_I] that was originally proposed by Alur and Henzinger, and we pin down their expressiveness as well as satisfaction complexities. We show that MITL[F_\inf,P_\inf] which has unary modalities with only lower-bound constraints is (surprisingly) expressively complete for Partially Ordered 2-Way Deterministic Timed Automata (po2DTA) and the reduction from logic to automaton gives us its NP-complete satisfiability. We also show that the fragment MITL[F_b,P_b] having unary modalities with only bounded intervals has \nexptime-complete satisfiability. But strangely, MITL[F_b,P_b] is strictly less expressive than MITL[F_\inf,P_\inf]. We provide a comprehensive picture of the decidability and expressiveness of various unary fragments of MITL.

Graph Logics with Rational Relations

Por • 27 abr, 2013 • Category: Crítica

We investigate some basic questions about the interaction of regular and rational relations on words. The primary motivation comes from the study of logics for querying graph topology, which have recently found numerous applications. Such logics use conditions on paths expressed by regular languages and relations, but they often need to be extended by rational relations such as subword or subsequence. Evaluating formulae in such extended graph logics boils down to checking nonemptiness of the intersection of rational relations with regular or recognizable relations (or, more generally, to the generalized intersection problem, asking whether some projections of a regular relation have a nonempty intersection with a given rational relation).