Title:
Color-critical graphs on surfaces

dc.contributor.advisor Thomas, Robin
dc.contributor.author Yerger, Carl Roger, Jr. en_US
dc.contributor.committeeMember Asaf Shapira
dc.contributor.committeeMember William Cook
dc.contributor.committeeMember William T. Trotter
dc.contributor.committeeMember Yu, Xingxing
dc.contributor.department Mathematics en_US
dc.date.accessioned 2011-03-04T20:22:16Z
dc.date.available 2011-03-04T20:22:16Z
dc.date.issued 2010-08-23 en_US
dc.description.abstract A graph is (t+1)-critical if it is not t-colorable, but every proper subgraph is. In this thesis, we study the structure of critical graphs on higher surfaces. One major result in this area is Carsten Thomassen's proof that there are finitely many 6-critical graphs on a fixed surface. This proof involves a structural theorem about a precolored cycle C of length q. In general terms, he proves that a coloring, c, of C, can be extended inside the cycle, or there exists a subgraph H with at most a number of vertices exponential in q such that c can not be extended to a 5-coloring of H. In Chapter 2, we proved an alternative proof that reduces the number of vertices in H to be cubic in q. In Chapter 3, we find the nine 6-critical graphs among all graphs embeddable on the Klein bottle. In Chapter 4, we prove a result concerning critical graphs related to an analogue of Steinberg's conjecture for higher surfaces. We show that if G is a 4-critical graph embedded on surface S, with Euler genus g and has no cycles of length four through ten, then G has at most 2442g + 37 vertices. en_US
dc.description.degree Ph.D. en_US
dc.identifier.uri http://hdl.handle.net/1853/37197
dc.publisher Georgia Institute of Technology en_US
dc.subject Graphs en_US
dc.subject Coloring en_US
dc.subject Steinberg en_US
dc.subject Critical en_US
dc.subject.lcsh Graph theory
dc.subject.lcsh Graph coloring
dc.title Color-critical graphs on surfaces en_US
dc.type Text
dc.type.genre Dissertation
dspace.entity.type Publication
local.contributor.corporatename College of Sciences
local.contributor.corporatename School of Mathematics
relation.isOrgUnitOfPublication 85042be6-2d68-4e07-b384-e1f908fae48a
relation.isOrgUnitOfPublication 84e5d930-8c17-4e24-96cc-63f5ab63da69
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