On the relationship of AP, RS and CEP in congruence modular varieties
The main result is that a congruence modular variety has the congruence extension property provided it is residually small, has the amalgamation property, a free algebra on four generators with congruence lattice of finite length, and its subdirectly irreducibles satisfy two commutator identities (C2) and (R) valid in the distributive case.
scientific article; zbMATH DE number 3983245
scientific article