Hostname: page-component-586b7cd67f-rdxmf Total loading time: 0 Render date: 2024-11-22T06:13:06.390Z Has data issue: false hasContentIssue false

DUALIZABILITY OF GRAPHS

Published online by Cambridge University Press:  24 February 2011

SARAH M. JOHANSEN*
Affiliation:
Department of Mathematics, La Trobe University, Victoria 3086, Australia (email: [email protected])
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

We investigate natural dualities for classes of simple graphs. For example, we give a natural duality for the class consisting of all n-colourable graphs and show that, for all n≥3, there is no natural duality for the class consisting of all freely n-colourable graphs. We also prove that there exist arbitrarily long finite chains of 3-colourable graphs that alternate between being dualizable and nondualizable.

Type
Research Article
Copyright
Copyright © Australian Mathematical Publishing Association Inc. 2011

References

[1]Banaschewski, B., ‘Projective covers in categories of topological spaces and topological algebras’, in: General Topology and its Relations to Modern Analysis and Algebra III (Proc. Conf., Kanpur, 1968) (Academia, Prague, 1971), pp. 6391.Google Scholar
[2]Banaschewski, B., ‘Remarks on dual adjointness’, in: Nordwestdeutsches Kategorienseminar (Bremen, 1976), Math.-Arbeitspapiere, 7, Teil A: Math. Forschungspapiere (Universität Bremen, Bremen, 1976), pp. 310.Google Scholar
[3]Caicedo, X., ‘Finitely axiomatisable quasivarieties of graphs’, Algebra Universalis 34 (1995), 314321.CrossRefGoogle Scholar
[4]Clark, D. M. and Davey, B. A., Natural Dualities for the Working Algebraist (Cambridge University Press, Cambridge, 1998).Google Scholar
[5]Clark, D. M., Davey, B. A. and Pitkethly, J. G., ‘Binary homomorphisms and natural dualities’, J. Pure Appl. Algebra 169 (2002), 128.CrossRefGoogle Scholar
[6]Clark, D. M., Idziak, P. M., Sabourin, L. R., Szabó, C. and Willard, R., ‘Natural dualities for quasivarieties generated by a finite commutative ring’, Algebra Universalis 46 (2001), 285320.CrossRefGoogle Scholar
[7]Davey, B. A., ‘Natural dualities for structures’, Acta Univ. M. Belii Ser. Math. 13 (2006), 328.Google Scholar
[8]Davey, B. A., Idziak, P. M., Lampe, W. A. and McNulty, G. F., ‘Dualizability and graph algebras’, Discrete Math. 214 (2000), 145172.CrossRefGoogle Scholar
[9]Davey, B. A. and Pitkethly, J. G., Dualisability: Unary Algebras and Beyond (Springer, Berlin, 2005).Google Scholar
[10]Davey, B. A., Pitkethly, J. G. and Willard, R., ‘The lattice of alter egos’, submitted.Google Scholar
[11]Davey, B. A. and Werner, H., ‘Dualities and equivalences for varieties of algebras’, in: Contributions to Lattice Theory, Colloquia Mathematica Societatis János Bolyai, 33 (North-Holland, Amsterdam, 1983), pp. 101275.Google Scholar
[12]Davey, B. A. and Willard, R., ‘The dualisability of a quasi-variety is independent of the generating algebra’, Algebra Universalis 45 (2001), 103106.CrossRefGoogle Scholar
[13]Hofmann, D., ‘A generalization of the duality compactness theorem’, J. Pure Appl. Algebra 171 (2002), 205217.CrossRefGoogle Scholar
[14]Jackson, M., ‘Dualisability of finite semigroups’, Internat. J. Algebra Comput. 13 (2003), 481497.CrossRefGoogle Scholar
[15]Johansen, S. M., ‘Dualisability of relational structures’, Houston J. Math., in press.Google Scholar
[16]Johansen, S. M., ‘Natural dualities: operations and their graphs’, submitted.Google Scholar
[17]Johansen, S. M., ‘Natural dualities for three classes of relational structures’, Algebra Universalis 63 (2010), 149170.CrossRefGoogle Scholar
[18]Lampe, W. A., McNulty, G. F. and Willard, R., ‘Full duality among graph algebras and flat graph algebras’, Algebra Universalis 45 (2001), 311334.Google Scholar
[19]Nešetřil, J. and Pultr, A., ‘On classes of relations and graphs determined by subobjects and factorobjects’, Discrete Math. 22 (1978), 287300.CrossRefGoogle Scholar
[20]Pitkethly, J. G., ‘Inherent dualisability’, Discrete Math. 269 (2003), 219237.CrossRefGoogle Scholar
[21]Quackenbush, R. and Szabó, C., ‘Nilpotent groups are not dualizable’, J. Aust. Math. Soc. 72 (2002), 173179.CrossRefGoogle Scholar
[22]Quackenbush, R. and Szabó, C., ‘Strong duality for metacyclic groups’, J. Aust. Math. Soc. 73 (2002), 377392.CrossRefGoogle Scholar
[23]Saramago, M. J., ‘Some remarks on dualisability and endodualisability’, Algebra Universalis 43 (2000), 197212.CrossRefGoogle Scholar
[24]Trotta, B., ‘Residual properties of simple graphs’, Bull. Aust. Math. Soc., in press.Google Scholar
[25]Wheeler, W. H., ‘The first order theory of n-colorable graphs’, Trans. Amer. Math. Soc. 250 (1979), 289310.Google Scholar