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Anticritical graphs

Published online by Cambridge University Press:  24 October 2008

Frank Harary
Affiliation:
University of Michigan
Carsten Thomassen
Affiliation:
Aarhus University

Abstract

The term ‘critical graph’ has been used most frequently to mean a graph such that the removal of any line decreases the chromatic number. This can be generalized to define a graph G to be ‘critical (μ)’ for an arbitrary invariant, μ if, for each line e, μ(Ge) ≠ μ(G). Analogously we may consider any line e which joins two points not already adjacent in G and define G as ‘anticritical (μ)’ if μ(G + e) ≠ μ(G). Anticritical graphs are investigated here with respect to the following invariants: chromatic number, line-chromatic number, point-connectivity, line-connectivity, point-independence number, line-independence number, diameter, radius, and cyclability number.

Type
Research Article
Copyright
Copyright © Cambridge Philosophical Society 1976

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References

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