Discrete Mathematics & Theoretical Computer Science, Vol 16, No 1 (2014)

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A combinatorial non-commutative Hopf algebra of graphs

Adrian Tanasa, Gerard H. E. Duchamp, Loic Foissy, Nguyen Hoang-Nghia, Dominique Manchon

Abstract


A non-commutative, planar, Hopf algebra of planar rooted trees was defined independently by one of the authors in Foissy (2002) and by R. Holtkamp in Holtkamp (2003). In this paper we propose such a non-commutative Hopf algebra for graphs. In order to define a non-commutative product we use a quantum field theoretical (QFT) idea, namely the one of introducing discrete scales on each edge of the graph (which, within the QFT framework, corresponds to energy scales of the associated propagators). Finally, we analyze the associated quadri-coalgebra and codendrifrom structures.

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