Abstract
Motivated by the work of Hofmann [14] and Davey [7] on dualities for structures, we will construct natural dualities for the classes of quasi-ordered sets, equivalence-relationed sets, and reflexive (undirected) graphs. We describe the dual structures by giving finite sets of quasi-equations that axiomatise the dual categories. We also show that there is a natural connection between the duality we construct for finite quasi-ordered sets and Birkhoff’s representation theorem for finite ordered sets [2], and between the dualities constructed for quasi-ordered sets and equivalence-relationed sets.
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References
Banaschewski, B.: Remarks on dual adjointness. In: Nordwestdeutsches Kategorienseminar (Bremen, 1976). Math.-Arbeitspapiere, vol. 7, pp. 3–10. Univ. Bremen, Bremen (1976)
Birkhoff G.: On the combination of subalgebras. Proc. Camb. Phil. Soc. 29, 441–464 (1933)
Clark D.M., Davey B.A.: Natural Dualities for the Working Algebraist. Cambridge University Press, Cambridge (1998)
Clark D.M., Davey B.A., Freese R.S., Jackson M.G.: Standard topological algebras: syntactic and principal congruences and profiniteness. Algebra Universalis 52, 343–376 (2004)
Clark D.M., Davey B.A., Haviar M., Pitkethly J.G., Talukder M.R.: Standard topological quasi-varieties. Houston J. Math. 29, 859–887 (2003)
Clark D.M., Davey B.A., Jackson M.G., Pitkethly J.G.: The axiomatizability of topological prevarieties. Advances in Mathematics 218, 1604–1653 (2008)
Davey B.A.: Natural dualities for structures. Acta Univ. M. Belii Ser. Math. 13, 3–28 (2006)
Davey B.A., Haviar M., Priestley H.A.: Boolean topological distributive lattices and canonical extensions. Appl. Categ. Structures 15, 225–241 (2007)
Davey, B.A., Pitkethly, J.G., Willard, R.: The lattice of alter egos. (preprint)
Davey B.A., Priestley H.A.: Introduction to Lattices and Order, 2nd edn. Cambridge University Press, Cambridge (2002)
Davey, B.A., Werner, H.: Dualities and equivalences for varieties of algebras. In: Contributions to lattice theory. Coll. Math. Soc. János Bolyai, vol. 33, pp. 101–275. North Holland (1983)
Grätzer, G.: General lattice theory, 2nd edn. Birkhäuser Verlag, Basel (1998)
Haviar, M., Ploščica, M.: Extension of Birkhoff’s duality to the class of all partially ordered sets. Preprint
Hofmann D.: A generalization of the duality compactness theorem. J. Pure Appl. Algebra 171, 205–217 (2002)
Jónsson B.: Algebras whose congruence lattices are distributive. Math. Scand. 21, 110–121 (1967)
Numakura K.: Theorems on compact totally disconnected semigroups and lattices. Proc. Amer. Math. Soc. 8, 623–626 (1957)
Priestley H.A.: Representation of distributive lattices by means of ordered Stone spaces. Bull. London Math. Soc. 2, 186–190 (1970)
Priestley H.A.: Ordered topological spaces and the representation of distributive lattices. Proc. London Math. Soc. 24, 507–530 (1972)
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Johansen, S.M. Natural dualities for three classes of relational structures. Algebra Univers. 63, 149–170 (2010). https://doi.org/10.1007/s00012-010-0074-3
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DOI: https://doi.org/10.1007/s00012-010-0074-3