Rees ideal algebras
We describe algebras and varieties for which every ideal is a kernel of a one-block congruence.
Reflexive relations and Mal'tsev conditions for congruence lattice identities in modular varieties
Regularity and permutability via transferability of tolerances
Regularity in arithmetical varieties
Regularity of algebras with applications to congruence class geometry
Relational characterizations of permutable and -permutable varieties
Remarks on equational theories of semilattices with operators