Pseudovariety

A class of finite algebras closed under taking finite direct products, subalgebras, and homomorphic images; usually considered within a fixed finite-signature algebraic context and relevant to finite-model and automata applications.

A class of finite algebras (for a fixed signature) closed under finite direct products, subalgebras, and homomorphic images; typically studied in the context of finite algebraic structures where infinitary closure properties are not appropriate.