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A concept of variety for regular biordered sets

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Abstract

We define a bivariety of regular biordered sets to be a nonempty class of regular biordered sets which is closed under taking direct products, regular bimorphic images and relatively regular biordered subsets. It is then shown that there is a complete lattice morphism mapping the complete lattice of all e-varieties of regular semigroups onto the complete lattice of all bivarieties of regular biordered sets; as a corollary we prove that there is a complete lattice morphism mapping the complete lattice of all e-varieties of E-solid regular semigroups onto the complete lattice of all varieties of solid binary algebras. Examples of bivarieties include the class of all solid regular biordered sets and the class of all local semilattices. For each setX with at least two elements, we show that a bivariety contains a free object onX if and only if it consists entirely of solid regular biordered sets or it consists entirely of local semilattices.

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References

  1. Auinger, K.,On the lattice of existence varieties of locally inverse semigroups, Can. Math. Bull. (to appear).

  2. Broeksteeg, R.,The set of idempotents of a completely regular semigroup as a binary algebra, Bull. Austral. Math. Soc. (to appear).

  3. Broeksteeg, R.,The structure of solid binary algebras, Preprint.

  4. Burris, S., and H. P. Sankappanavar, “A Course in Universal Algebra”, Graduate Texts in Mathematics78, Springer-Verlag, New York, Heidelberg, Berlin, 1981.

    MATH  Google Scholar 

  5. Clifford, A. H.,The fundamental representation of a completely regular semigroup, Semigroup Forum12 (1976), 341–346.

    Article  MATH  MathSciNet  Google Scholar 

  6. Clifford, A. H., and G. B. Preston, “The Algebraic Theory of Semigroups”, 2nd ed., Math. Surveys No. 7, Amer. Math. Soc., Providence, R. I., 1961 (reprinted 1988).

    MATH  Google Scholar 

  7. Easdown, D.,Biordered sets of bands, Semigroup Forum29 (1984), 241–246.

    Article  MATH  MathSciNet  Google Scholar 

  8. Easdown, D.,Biordered sets of eventually regular semigroups, Proc. London Math. Soc. (3)49 (1984), 483–503.

    Article  MATH  MathSciNet  Google Scholar 

  9. Easdown, D.,Biordered sets come from semigroups, J. Algebra96 (1985), 581–591.

    Article  MATH  MathSciNet  Google Scholar 

  10. Easdown, D.,Biordered sets of some interesting classes of semigroups, Proceedings International Symposium on Regular Semigroups and Applications, University of Kerala (1986).

  11. Hall, T. E.,On regular semigroups, J. Algebra24 (1973), 1–24.

    Article  MATH  MathSciNet  Google Scholar 

  12. Hall, T. E.,Identities for existence varieties of regular semigroups, Bull. Austral. Math. Soc.40 (1989), 59–77.

    Article  MATH  MathSciNet  Google Scholar 

  13. Hall, T. E.,Regular semigroups: amalgamation and the lattice of existence varieties, Algebra Universalis28 (1991), 79–102.

    Article  MATH  MathSciNet  Google Scholar 

  14. Higgins, P. M., “Techniques of Semigroup Theory”, Oxford University Press, 1992.

  15. Howie, J. M., “An Introduction to Semigroup Theory”, London Math. Soc. Monographs 7, Academic Press, London, New York, 1976.

    MATH  Google Scholar 

  16. Meakin, J.,Local semilattices on two generators, Semigroup Forum24 (1982), 95–116.

    Article  MATH  MathSciNet  Google Scholar 

  17. Meakin, J.,The free local semilattice on a set, J. Pure Appl. Algebra27 (1983), 263–275.

    Article  MATH  MathSciNet  Google Scholar 

  18. Meakin, J., and K. S. S. Nambooripad,Coextensions of regular semigroups by rectangular bands I, Trans. Amer. Math. Soc.269 (1982), 197–224.

    Article  MATH  MathSciNet  Google Scholar 

  19. Meakin, J., and F. Pastijn,The structure of pseudo-semilattices, Algebra Universalis13 (1981), 355–372.

    Article  MATH  MathSciNet  Google Scholar 

  20. Meakin, J., and F. Pastijn,The free pseudo-semilattice on two generators, Algebra Universalis14 (1982), 297–309.

    Article  MATH  MathSciNet  Google Scholar 

  21. Nambooripad, K. S. S.,Structure of regular semigroups I: Fundamental regular semigroups, Semigroup Forum9 (1975), 354–363.

    Article  MathSciNet  Google Scholar 

  22. Nambooripad, K. S. S.,Structure of regular semigroups I, Mem. Amer. Math. Soc.22 (1979), no. 224.

  23. Nambooripad, K. S. S.,Pseudo-semilattices and biordered sets I, Simon Stevin55 (1981), 103–110.

    MATH  MathSciNet  Google Scholar 

  24. Yeh, Y. T.,The existence of e-free objects in e-varieties of regular semigroups, Internat. J. Algebra Comput.2 (1992), 471–484.

    Article  MATH  MathSciNet  Google Scholar 

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Communicated by T. E. Hall

The author gratefully acknowledges the financial support of an Australian Postgraduate Research Award.

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Broeksteeg, R. A concept of variety for regular biordered sets. Semigroup Forum 49, 335–348 (1994). https://doi.org/10.1007/BF02573495

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