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arXiv · 1110.4977

On 2-switches and isomorphism classes

Michael D. Barrus
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Abstract

A 2-switch is an edge addition/deletion operation that changes adjacencies in the graph while preserving the degree of each vertex. A well known result states that graphs with the same degree sequence may be changed into each other via sequences of 2-switches. We show that if a 2-switch changes the isomorphism class of a graph, then it must take place in one of four configurations. We also present a sufficient condition for a 2-switch to change the isomorphism class of a graph. As consequences, we give a new characterization of matrogenic graphs and determine the largest hereditary graph family whose members are all the unique realizations (up to isomorphism) of their respective degree sequences.

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Michael D. Barrus. 2011-10-22. On 2-switches and isomorphism classes. https://doi.org/10.1016/j.disc.2012.04.014

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