The necklace Lie coalgebra and renormalization algebras

  • Wee Liang Gan

    UC Riverside
  • Travis Schedler

    University of Chicago


We give a natural monomorphism from the necklace Lie coalgebra, defined for any quiver, to Connes and Kreimer’s Lie coalgebra of trees, and extend this to a map from a certain quiver-theoretic Hopf algebra to Connes and Kreimer’s renormalization Hopf algebra as well as to pre-Lie versions. These results are direct analogues of Turaev’s results in 2004, by replacing algebras of loops on surfaces with algebras of paths on quivers. We also factor the morphism through an algebra of chord diagrams and explain the geometric version. We then describe how all of the Hopf algebras are uniquely determined by the pre-Lie structures and discuss noncommutative versions of the Hopf algebras.

Cite this article

Wee Liang Gan, Travis Schedler, The necklace Lie coalgebra and renormalization algebras. J. Noncommut. Geom. 2 (2008), no. 2, pp. 195–214

DOI 10.4171/JNCG/19