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math.CO2024
The Heawood approach to Tait colorings and defining vertex sets
E. Yu. Lerner
Given a simple biconnected planar cubic graph, we associate each its vertex among ones with the so-called spin, i.e., a variable which takes on values . P. J. Heawood h…
math.CO2024
Matroid variant of Matiyasevich formula and its application
E. Yu. Lerner
In 1977, Yu. V. Matiyasevich proposed a formula expressing the chromatic polynomial of an arbitrary graph as a linear combination of flow polynomials of subgraphs of the original g…