A Tableaux Calculus for Reducing Proof Size

A tableau calculus is proposed, based on a compressed representation of clauses, where literals sharing a similar shape may be merged. The inferences applied on these literals are fused when possible, which reduces the size of the proof. It is shown that the obtained proof procedure is sound, refutationally complete and allows to reduce the size of the tableau by an exponential factor. The approach is compatible with all usual refinements of tableaux.Comment: Technical Repor

35: Justice of the Peace appointment, 1792: Manuel Gayoso do Lemos to William Dunbar

Justice of the Peace appointment, 1792: Manuel Gayoso do Lemos to William Dunbarhttps://scholarlycommons.obu.edu/dunbar/1037/thumbnail.jp

Satisfiability of constraint specifications on XML documents

Jose Meseguer is one of the earliest contributors in the area of Algebraic Specification. In this paper, which we are happy to dedicate to him on the occasion of his 65th birthday, we use ideas and methods coming from that area with the aim of presenting an approach for the specification of the structure of classes of XML documents and for reasoning about them. More precisely, we specify the structure of documents using sets of constraints that are based on XPath and we present inference rules that are shown to define a sound and complete refutation procedure for checking satisfiability of a given specification using tableaux.Peer ReviewedPostprint (author's final draft

Time complexity of concurrent programs: a technique based on behavioural types

International audienceWe study the problem of automatically computing the time complexity of concurrent object-oriented programs. To determine this complexity we use intermediate abstract descriptions that record relevant information for the time analysis (cost of statements, creations of objects, and concurrent operations), called behavioural types. Then, we define a translation function that takes behavioural types and makes the parallelism explicit into so-called cost equations , which are fed to an automatic off-the-shelf solver for obtaining the time complexity