20 research outputs found
A-ordered tableaux
In resolution proof procedures refinements based on A-orderings of
literals have a long tradition and are well investigated. In
tableau proof procedures such refinements were only recently
introduced by the authors of the present paper. In this paper we
prove the following results: we give a completeness proof of
A-ordered ground clause tableaux which is a lot easier to follow
than the previous one. The technique used in the proof is extended
to the non-clausal case as well as to the non-ground case and we
introduce an ordered version of Hintikka sets that shares the model
existence property of standard Hintikks sets. We show that
A-ordered tableaux are a proof confluent refinement of tableaux and
that A-ordered tableaux together with the connection refinement
yield an incomplete proof procedure. We introduce A-ordered
first-order NNF tableaux, prove their completeness, and we briefly
discuss implementation issues
Deduction by combining semantic tableaux and integer programming
. In this paper we propose to extend the current capabilities of automated reasoning systems by making use of techniques from integer programming. We describe the architecture of an automated reasoning system based on a Herbrand procedure (enumeration of formula instances) on clauses. The input are arbitrary sentences of first-order logic. The translation into clauses is done incrementally and is controlled by a semantic tableau procedure using unification. This amounts to an incremental polynomial CNF transformation which at the same time encodes part of the tableau structure and, therefore, tableau-specific refinements that reduce the search space. Checking propositional unsatisfiability of the resulting sequence of clauses can either be done with a symbolic inference system such as the Davis-Putnam procedure or it can be done using integer programming. If the latter is used a number of advantages become apparent. Introduction In this paper we propose to extend the current capabilit..
Model generation theorem proving with interval constraints
We investigate how the deduction paradigm of model generation
theorem proving can be enhanced with interval-and extraval-based
constraints leading to more efficient model generation in for some
finite domain problems