Abstract
This paper considers the lattice of subquasivarieties of a regular variety. In particular we show that if V is a strongly irregular variety that is minimal as a quasivariety, then the smallest quasivariety containing both V and SI (the variety of semilattices) is never equal to the regularization V of V.
We use this result to describe the lattice of subquasivarieties of V in several special but quite common, cases and give a number of applications and examples.
Similar content being viewed by others
References
Bergman, C.,Structural completeness in algebra and logic, Colloq. Math. Soc. J. Bolyai54 (1988), 59–73.
Berman, J.,Free spectra of 3-element algebras, Springer Lecture Notes in Mathematics1004 (1983), 10–53.
Bergman, C. andMcKenzie, R.,Minimal varieties and quasivarieties, J. Austral. Math. Soc. (Series A)48 (1990), 133–147.
Burris, S. andSankappanavar, H. P.,A Course in Universal Algebra, Springer-Verlag, New York, 1981.
Clark, D. M. andKrauss, P. H.,Para primal algebras, Algebra Universalis6 (1976), 165–192.
Csákány, B. andMegyesi, L.,Varieties of idempotent medial quasigroup, Acta Sci. Math.37 (1975), 17–23.
Csákány, B.,Varieties of affine modules, Acta Sci. Math.37 (1975), 3–10.
Dudek, J. andGraczyinska, E.,The lattice of varieties of algebras, Bull. Acad. Polon. Sci. Ser. Sci. Math.29 (1981), 337–340.
Davey, B. A., Miles, K. R. andSchumann, V. J.,Quasi-identities, Mal'cev conditions and congruence regularity, Acta Sci. Math.51 (1987), 39–55.
Freese, R. andMcKenzie, R.,Commutator Theory for Congruence Modular Varieties, London Mathematical Society Lecture Notes no. 125, Cambridge University Press, Cambridge, 1987.
Grätzer, G.,Universal Algebra, Second edition, Springer-Verlag, New York, 1979.
Gierz, G. andRomanowska, A.,Duality for distributive bisemilattices, J. Austral. Math. Soc. (Series A)51 (1991), 247–275.
Guzmán, F.,Three-valued logic in the semantics of programming languages (Preprint, 1992).
Hogben, L. andBergman, C.,Deductive varieties of modules and universal algebras, Trans. Amer. Math. Soc.289 (1985), 303–320.
Igosin, V. I.,Quasivarieties of lattices, Mat. Z.16 (1974), 49–56 (Russian); English Transl., Math. Notes16 (1974), 613–617.
Jeźek, J. andKepka, T.,The lattice of varieties of commutative idempotent abelian distributive groupoids, Algebra Universalis5 (1975), 225–237.
Kearnes, K.,Idempotent simple algebras, Logic and Algebra, Proceedings of the Magari Memorial Conference, Siena, 1994, Marcel Dekker, New York.
Kalman, J. A.,The join of the varieties of implication algebras and semilattices, Math. Chronicle9 (1980), 41–52.
Kalicki, J. andScott, D.,Equational completeness of abstract algebras, Indag. Math.17 (1955), 650–659.
Libkin, L.,Towards a theory of edible powerdomains (Preprint, 1993).
Lakser, H., Padmanabhan, R. andPlatt, C. R.,Subdirect decomposition of Plonka sums, Duke Math. Journal39 (1972), 485–488.
Mal'cev, A. I.,Algebraic Systems, Springer-Verlag, Berlin, 1973.
Mal'nik, I. I.,Normal closures of perfect varieties of universal algebras, Ordered sets and Lattices, Izdat. Saratov. Univ., Saratov, (1971), 56–65 (Russian).
Mitschke, A.,Summen von gerichteten Systemen von Algebren, Mitt. Math. Sem. Giessen124 (1977), 1–56.
McKenzie, R., McNulty, G. andTaylor, T.,Algebras, Lattices, Varieties, vol. 1, Wadsworth, Monterey, 1987.
Osterman, F. andSchmidt, J.,Der baryzentrische Kalkul als axiomatische Grundlage der affinen Geometrie, J. Reine Angew. Math.224 (1966), 44–57.
Płonka, J.,On a method of construction of abstract algebras, Fund. Math.61 (1967), 183–189.
Płonka, J.,On distributive quasilattices, Fund. Math.60 (1967), 191–200.
Płonka, J.,On equational classes of abstract algebras defined by regular equations, Fund. Math.64 (1969), 241–247.
Płonka, J.,On sums of direct systems of Boolean algebras, Coll. Math.20 (1969), 209–214.
Płonka, J. andRomanowska, A.,Semilattice sums, Universal Algebra and Quasigroup Theory (A. Romanowska and J. D. H. Smith, eds.), Heldermann Verlag, Berlin, 1992, pp. 123–158.
Pilitowska, A.,Romanowska, A. andRoszkowska, B.,Products of mode varieties and algebras of subalgebras, Math. Slovaca (to appear).
Pilitowska, A., Romanowska, A. andSmith, J. D. H.,Affine spaces and algebras of subalgebras, Algebra Universalis34 (1995), 527–540.
Puhlmann, H.,The snack power domain for database semantics, MFCS-93, pp. 650–659.
Quackenbush, R. W.,Algebras with minimal spectrum, Algebra Universalis10 (1980), 117–129.
Romanowska, A.,On regular and regularized varieties, Algebra Universalis23 (1986), 215–241.
Roszkowska, B.,On some varieties of symmetric idempotent entropic groupoids, Universal and Applied Algebra (K. Halkowska and B. Stawski, eds.), World Scientific, 1989, pp. 254–274.
Romanowska, A. andSmith, J. D. H.,From Affine to projective geometry via convexity, Springer Lecture Notes in Mathematics1149 (1985), 255–270.
Romanowska, A. andSmith, J. D. H.,Modal Theory, Heldermann Verlag, Berlin, 1985.
Romanowska, A. andSmith, J. D. H.,On the structure of semilattice sums, Czechoslovak J. Math.41 (1991), 24–43.
Romanowska, A. andSmith, J. D. H.,Duality for semilattice representations, Jour. Pure and Appl. Algebra (to appear).
Szendrei, Á.,On idempotent reducts of modules I, II, Colloq. Math. Soc. J. Bolyai29 (1982), 753–768, 769–780.
Szendrei, Á.,Strictly simple algebras and minimal varieties, Universal Algebra and Quasigroup Theory (A. Romanowska and J. D. H. Smith, eds.), Heldermann Verlag, Berlin, 1992, pp. 209–239.
Szendrei, Á.,Simple surjective algebras having no proper subalgebras, J. Australian Math. Soc. (Series A)48 (1990), 434–454.
Tarski, A.,Equationally complete rings and relation algebras, Indag. Math.18 (1956), 39–46.
Author information
Authors and Affiliations
Additional information
Work on this paper was begun while the second author was visiting Iowa State University during the summer of 1994.
Rights and permissions
About this article
Cite this article
Bergman, C., Romanowska, A. Subquasivarieties of regularized varieties. Algebra Universalis 36, 536–563 (1996). https://doi.org/10.1007/BF01233924
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF01233924