Abstract
We call a simple graph G a 4-cycled graph if either it has no edges or every edge of it is contained in an induced 4-cycle of G. Our interest on 4-cycled graphs is motivated by the fact that their clique complexes play an important role in the simple-homotopy theory of simplicial complexes. We prove that the minimal simple models within the category of flag simplicial complexes are exactly the clique complexes of some 4-cycled graphs. We further provide structural properties of 4-cycled graphs and describe constructions yielding such graphs. We characterize 4-cycled cographs, and 4-cycled graphs arising from finite chessboards. We introduce a family of inductively constructed graphs, the external extensions, related to an arbitrary graph, and determine the homotopy type of the independence complexes of external extensions of some graphs.
Similar content being viewed by others
References
Barmak J.A., Minian E.G.: Minimal finite models. J. Homotopy Relat. Struct. 2(1), 127–140 (2007)
Barmak J.A., Minian E.G.: Simple homotopy types and finite spaces. Adv. Math. 218(1), 87–104 (2008)
Boulet R., Fieux E., Jouve B.: Simplicial simple homotopy of flag complexes in terms of graphs. European J. Combin. 31(1), 161–176 (2010)
Brandstädt, A., Le, B.V., Spinrad, J.P.: Graph Classes: A Survey. Society for Industrial and Applied Mathematics (SIAM), Philadelphia, PA (1999)
Cohen M.M.: A Course in Simple-Homotopy Theory. Springer-Verlag, New York (1973)
Corneil D.G., Lerchs H., Burlingham L.S.: Complement reducible graphs. Discrete Appl. Math., 3(3), 163–174 (1981)
Dochtermann, A., Engström, A.: Algebraic properties of edge ideals via combinatorial topology. Electronic J. Combin. 16(2), #R2 (2009)
Ehrenborg R., Hetyei G.: The topology of the independence complex. European J. Combin. 27(6), 906–923 (2006)
Hatcher A.: Algebraic Topology. Cambridge University Press, Cambridge (2001)
Kozlov D.: Combinatorial Algebraic Topology. Springer, Berlin (2008)
Marietti M., Testa D.: Cores of simplicial complexes. Discrete Comput. Geom. 40(3), 444–468 (2008)
Lovász L.: Kneser’s conjecture, chromatic number, and homotopy. J. Combin. Theory Ser. A 25(3), 319–324 (1978)
Villarreal R.H.: Cohen-Macaulay graphs. Manuscripta Math. 66(3), 277–293 (1990)
Wachs M.L.: Topology of matching, chessboard, and general bounded degree graph complexes. Algebra Universalis 49(4), 345–385 (2003)
Author information
Authors and Affiliations
Corresponding author
Additional information
Both authors are supported by TÜBA through Young Scientist Award Program (TÜBA-GEBIİP/2009-06 and 2008-08).
Rights and permissions
About this article
Cite this article
Bıyıkoğlu, T., Civan, Y. Four-Cycled Graphs with Topological Applications. Ann. Comb. 16, 37–56 (2012). https://doi.org/10.1007/s00026-011-0120-7
Received:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00026-011-0120-7