Publications
On regular implicit operations. Portugal. Math.. 1993;50:35-61.Edit
Representation theory of finite semigroups, semigroup radicals and formal language theory. Trans. Amer. Math. Soc.. 2009;361:1429-1461.Edit
Residually finite congruences and quasi-regular subsets in uniform algebras. Portugal. Math.. 1989;46:313-328.Edit
SC-hyperdecidability of $\bf R$. Theoret. Comput. Sci.. 2001;255:569-591.Edit
Semidirect product with an order-computable pseudovariety and tameness. Semigroup Forum. 2010;81:26-50.Edit
Semidirect products of pseudovarieties from the universal algebraist's point of view. J. Pure Appl. Algebra. 1989;60:113-128.Edit
Semidirectly closed pseudovarieties of locally trivial semigroups. Semigroup Forum. 1990;40:315-323.Edit
Semigroups whose idempotents form a subsemigroup. Math. Proc. Cambridge Philos. Soc.. 1992;111:241-253.Edit
Semisimple synchronizing automata and the Wedderburn-Artin theory. Internat. J. Foundat. Comput. Sci.. 2016;27(2):127-145.Edit
A sequence of weakly monotonic automata with increasing level. Int. J. Algebra. 2013;7:91-100.Edit
Some algorithmic problems for pseudovarieties. Publ. Math. Debrecen. 1999;54:531-552.Edit
Some algorithms on the star operation applied to finite languages. Semigroup Forum. 1984;28:187-197.Edit
Some key problems on finite semigroups. Semigroup Forum. 2002;64:159-179.Edit
Some order properties of the lattice of varieties of commutative semigroups. Canad. J. Math.. 1986;38:19-47.Edit
Some pseudovariety joins involving the pseudovariety of finite groups. Semigroup Forum. 1988;37:53-57.Edit
Some quasi-ordered classes of finite commutative semigroups. Semigroup Forum. 1985;32:189-200.Edit
Subword complexity of profinite words and subgroups of free profinite semigroups. Internat. J. Algebra Comput.. 2006;16:221-258.Edit
Sur certains systèmes d'équations avec contraintes dans un groupe libre. Portugal. Math.. 1999;56:409-417.Edit
Sur certains systèmes d'équations avec contraintes dans un groupe libre–-addenda. Port. Math. (N.S.). 2001;58:379-387.Edit
A syntactical proof of locality of DA. Internat. J. Algebra Comput.. 1996;6:165-177.Edit
Tameness of pseudovarieties of semigroups. S\=urikaisekikenky\=usho Kōky\=uroku. 2000:8-16.Edit
Tameness of pseudovariety joins involving R. Monatsh. Math.. 2005;146:89-111.Edit
Tameness of some locally trivial pseudovarieties. Comm. Algebra. 2003;31:61-77.Edit
Tameness of the pseudovariety of abelian groups. Internat. J. Algebra Comput.. 2005;15:327-338.Edit
On the topological semigroup of equational classes of finite functions under composition. J. of Mult.-Valued Logic & Soft Computing. 2017;28(1):5-28.Edit