Conditional Answer Computation in SOL as Speculative Computation in Multi-Agent Environments1 1This research was supported partly by Grant-in-Aid from The Ministry of Education, Science and Culture of Japan.

AbstractIn this paper, we study speculative computation in a master-slave multi-agent system where reply messages sent from slave agents to a master are always tentative and may change from time to time. In this system, default values used in speculative computation are only partially determined in advance. Inoue et al. [8] formalized speculative computation in such an environment with tentative replies, using the framework of a first-order consequence-finding procedure SOL with the well-known answer literal method. We shall further refine the SOL calculus, using conditional answer computation and skip-preference in SOL. The conditional answer format has an great advantage of explicitly representing how a conclusion depends on tentative replies and defaults, both of which are used to derive the conclusion. The dependency representation is significantly important to avoid unnecessary recomputation of tentative conclusions. The skip-preference has the great ability of preventing irrational/redundant derivations

An inference rule for hypothesis generation

There are many new application fields for automated deduction where we have to apply abductive reasoning. In these applications we have to generate consequences of a given theory having some appropriate properties. In particular we consider the case where we have to generate the clauses containing instances of a given literal L. The negation of the other literals in such clauses are hypothesis allowing to derive L. In this paper we present an inference rule, called L-inference, which was designed in order to derive those clauses, and a L-strategy. The L-inference rule is a sort of Input Hyperresolution. The main result of the paper is the proof of the soundness and completeness of the L-inference rule. The L-strategy associated to the L-inference rule, is a saturation by level with deletion of the tautologies and of the subsumed clauses. We show that the L-strategy is also complete.