Publications
The pseudovariety $\bf J$ is hyperdecidable. RAIRO Inform. Théor. Appl.. 1997;31:457-482.Edit
A syntactical proof of locality of DA. Internat. J. Algebra Comput.. 1996;6:165-177.Edit
Free profinite semigroups over semidirect products. Izv. Vyssh. Uchebn. Zaved. Mat.. 1995:3-31.Edit
The mathematician Hugo Ribeiro. Portugal. Math.. 1995;52:1-14.Edit
Relatively free profinite monoids: an introduction and examples. In: Semigroups, formal languages and groups (York, 1993). Vol 466. Kluwer Acad. Publ., Dordrecht; 1995. 7. p. 73-117p. (NATO Adv. Sci. Inst. Ser. C Math. Phys. Sci.; vol 466).Edit
A classification of aperiodic power monoids. J. Algebra. 1994;170:355-387.Edit
Finite semigroups and universal algebra. Vol 3 World Scientific Publishing Co., Inc., River Edge, NJ 1994.Edit
Reduced factorizations in free profinite groups and join decompositions of pseudovarieties. Internat. J. Algebra Comput.. 1994;4:375-403.Edit
Implicit operations and Knast's theorem. In: Semigroups (Luino, 1992). World Sci. Publ., River Edge, NJ; 1993. 1. p. 1-16p. Edit
Locally commutative power semigroups and counting factors of words. Theoret. Comput. Sci.. 1993;108:3-16.Edit
On regular implicit operations. Portugal. Math.. 1993;50:35-61.Edit
A unified syntactical approach to theorems of Putcha, Margolis, and Straubing on finite power semigroups. Semigroup Forum. 1993;46:90-97.Edit
Counting factors in words, semidirect products and power semigroups. In: Words, languages and combinatorics (Kyoto, 1990). World Sci. Publ., River Edge, NJ; 1992. 1. p. 1-15p. Edit
On the power semigroup of a finite semigroup. Portugal. Math.. 1992;49:295-331.Edit
Semigroups whose idempotents form a subsemigroup. Math. Proc. Cambridge Philos. Soc.. 1992;111:241-253.Edit
On direct product decompositions of finite $\scr J$-trivial semigroups. Internat. J. Algebra Comput.. 1991;1:329-337.Edit
On finite simple semigroups. Proc. Edinburgh Math. Soc. (2). 1991;34:205-215.Edit
Implicit operations on finite $\scr J$-trivial semigroups and a conjecture of I. Simon. J. Pure Appl. Algebra. 1991;69:205-218.Edit
On iterated semidirect products of finite semilattices. J. Algebra. 1991;142:239-254.Edit
On the membership problem for pseudovarieties of commutative semigroups. Semigroup Forum. 1991;42:47-51.Edit
Recent developments in the theory of implicit operations. In: Monoids and semigroups with applications (Berkeley, CA, 1989). World Sci. Publ., River Edge, NJ; 1991. 1. p. 105-117p. Edit
Semigrupos finitos e álgebra universal Universidade de São Paulo, Instituto de Matemática e Estatí stica, São Paulo 1991.Edit
An elementary proof that finite groups are projectively torsion-free. Portugal. Math.. 1990;47:437-444.Edit
The equation $\bf PX=\bf PJ$. In: Proceedings of the International Symposium on the Semigroup Theory and its Related Fields (Kyoto, 1990). Shimane Univ., Matsue; 1990. 1. p. 1-11p. Edit
On pseudovarieties, varieties of languages, filters of congruences, pseudoidentities and related topics. Algebra Universalis. 1990;27:333-350.Edit