- International Electronic Journal of Algebra
- Volume:30 Issue:30
- CHROMATIC POLYNOMIALS AND BIALGEBRAS OF GRAPHS
CHROMATIC POLYNOMIALS AND BIALGEBRAS OF GRAPHS
Authors : Loic FOISSY
Pages : 116-167
Doi:10.24330/ieja.969651
View : 46 | Download : 10
Publication Date : 2021-07-17
Article Type : Research Paper
Abstract :The chromatic polynomial is characterized as the unique polynomial invariant of graphs, compatible with two interacting bialgebras structures: the first coproduct is given by partitions of vertices into two parts, the second one by a contraction-extraction process. This gives Hopf-algebraic proofs of Rota`s result on the signs of coefficients of chromatic polynomials and of Stanley`s interpretation of the values at negative integers of chromatic polynomials. We also consider chromatic symmetric functions and their noncommutative versions.Keywords : Bialgebras in cointeraction, chromatic polynomial, chromatic symmetric function
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