Reasoning within extended fuzzy description logic

An extended fuzzy description logic is proposed to increase expressive power for complex fuzzy information. We introduce cut sets of the fuzzy concepts and fuzzy roles as atomic concepts and atomic roles, and inherit concept constructors of the description logics to support a new logic system for fuzzy knowledge representation. We define the syntax, semantics and knowledge base of the extended fuzzy description logic, and focus on sat-domain and consistency as main reasoning tasks. We also present sound and complete tableau algorithms for these reasoning tasks, and prove the complexity of them is PSPACE-complete. Compared with the other fuzzy description logics, the extended fuzzy description logic can express more wide fuzzy information.