5-Choosability of Planar-plus-two-edge Graphs
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Date
2018-01-02
Authors
Mahmoud, Amena
Journal Title
Journal ISSN
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Publisher
University of Waterloo
Abstract
We prove that graphs that can be made planar by deleting two edges are 5-choosable. To arrive at this, first we prove an extension of a theorem of Thomassen. Second, we prove an extension of a theorem Postle and Thomas. The difference between our extensions and the theorems of Thomassen and of Postle and Thomas is that we allow the graph to contain an inner 4-list vertex. We also use a colouring technique from two papers by Dvořák, Lidický and Škrekovski, and independently by Compos and Havet.