Equational logic and theories in sentential languages
Equational Reformulation Of Formal Theories
Equational spectrum of Hilbert varieties
We prove that an equational class of Hilbert algebras cannot be defined by a single equation. In particular Hilbert algebras and implication algebras are not one-based. Also, we use a seminal theorem of Alfred Tarski in equational logic to characterize the set of cardinalities of all finite irredundant bases of the varieties of Hilbert algebras, implication algebras and commutative BCK algebras: all these varieties can be defined by independent bases of n elements, for each n > 1.
Equational theories of some almost unary groupoids
Equational Theories of Varieties defined by P-compatible Identities of Boole'an Algebras
Equationally compact algebras (I)
Equationally compact algebras II
Equationally compact algebras (III)
Equations on the semidirect product of a finite semilattice by a finite commutative monoid.
Equimorphy in varieties of distributive double -algebras
Any finitely generated regular variety of distributive double -algebras is finitely determined, meaning that for some finite cardinal , any subclass of algebras with isomorphic endomorphism monoids has fewer than pairwise non-isomorphic members. This result follows from our structural characterization of those finitely generated almost regular varieties which are finitely determined. We conjecture that any finitely generated, finitely determined variety of distributive double -algebras...
Equimorphy in varieties of double Heyting algebras
We show that any finitely generated variety V of double Heyting algebras is finitely determined, meaning that for some finite cardinal n(V), any class ⊆ V consisting of algebras with pairwise isomorphic endomorphism monoids has fewer than n(V) pairwise non-isomorphic members. This result complements the earlier established fact of categorical universality of the variety of all double Heyting algebras, and contrasts with categorical results concerning finitely generated varieties of distributive...
Equivalence relations defined by automorphism groups
Equivalence Systems with Finitely Many Relations.
Equivalences, a-semigroups and a-congruences.
Equivariant Homology and Mackey Functors.
Errata for the paper "Equationally compact algebras II" (Fundamenta Mathematica 61 (1968), pp. 271-281)
Essentially equational categories
Etude du treillis des congruences à droite sur le monoide bicyclique.
E-varieties of regular semigroups, relatively bifree objects and fully invariant congruences.
Even equations and Agassiz sums