English

Hopf algebra structure of generalized quasi-symmetric functions in partially commutative variables

Combinatorics 2021-07-02 v4 Mathematical Physics math.MP Rings and Algebras Exactly Solvable and Integrable Systems

Abstract

We introduce a coloured generalization NSymA\mathrm{NSym}_A of the Hopf algebra of non-commutative symmetric functions described as a subalgebra of the of rooted ordered coloured trees Hopf algebra. Its natural basis can be identified with the set of sentences over alphabet AA (the set of colours). We present also its graded dual algebra QSymA\mathrm{QSym}_A of coloured quasi-symmetric functions together with its realization in terms of power series in partially commutative variables. We provide formulas expressing multiplication, comultiplication and the antipode for these Hopf algebras in various bases -- the corresponding generalizations of the complete homogeneous, elementary, ribbon Schur and power sum bases of NSym\mathrm{NSym}, and the monomial and fundamental bases of QSym\mathrm{QSym}. We study also certain distinguished series of trees in the setting of restricted duals to Hopf algebras.

Keywords

Cite

@article{arxiv.1603.03259,
  title  = {Hopf algebra structure of generalized quasi-symmetric functions in partially commutative variables},
  author = {Adam Doliwa},
  journal= {arXiv preprint arXiv:1603.03259},
  year   = {2021}
}

Comments

22(->28) pages, 11(->13) figures; introduction expanded and references added (v2); new parts concerning the antipodes, and the fundamental and ribbon bases, the appendix removed (v3); new section on restricted duals and coloured non-commutative power sum functions added (v4)