Congruence-based proofs of the recognizability theorems for free many-sorted algebras
Juan Climent Vidal, Enric Cosme Llópez · Journal of Logic and Computation · 2019
Abstract We generalize several recognizability theorems for free single-sorted algebras to free many-sorted algebras and provide, in a uniform way and without using either regular tree grammars or tree automata, purely algebraic proofs of them based on congruences.