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On the sum of all distances in chromatic blocks. (English) Zbl 0789.05036
The author has constructed 2-connected $$k$$-chromatic graphs of order $$n$$ with the maximum sum of all distances between their vertices. The extremal graphs are cycles and complete graphs as well as some of their modifications. Also several auxiliary results are given on chromatic critical graphs and blocks.

##### MSC:
 05C12 Distance in graphs 05C15 Coloring of graphs and hypergraphs 05C35 Extremal problems in graph theory
##### Keywords:
chromatic graphs; distances; extremal graphs; cycles; complete graphs
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##### References:
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