4 papers
Minimal non-extensible precolorings and implicit-relations
José Antonio Martín H
In this paper I study a variant of the general vertex coloring problem called precoloring. Specifically, I study graph precolorings, by developing new theory, for characterizing th…
A polynomial 3-colorability algorithm with automatic generation of NO 3-colorability (i.e. Co-NP) short proofs
Jose Antonio Martin H
In this paper, an algorithm for determining 3-colorability, i.e. the decision problem (YES/NO), in planar graphs is presented. The algorithm, although not exact (it could produce f…
Upper-critical graphs
Jose Antonio Martin H
This work introduces the concept of \emph{upper-critical graphs}, in a complementary way of the conventional (lower)critical graphs: an element of a graph is called \emph{c…
Graph-Chromatic Implicit Relations
Jose Antonio Martin H
A theory about the implication structure in graph coloring is presented. Discovering hidden relations is a crucial activity in every scientific discipline. The development of mathe…