chaining backward
3.This paper is concerned mainly with how to use Concurrent Smalltalk-80 to implement parallelinference engine of production rules in expert system which is based on the sequential reasoningand with the way of forward chaining reasoning and backward chaining deduction. Matching com-plexity is also discussed.
8.Proposed in this paper is a non-backtrace backward chaining Web services dynamic composition framework based on mediator. Under this framework, a rule modeling method in composition and a parameter-level ontology for eliminating the composition semantic conflict are provided, and then a non-backtrace backward chaining algorithm is used to compose Web services.

