We introduce the concept of para-Hopf algebroid and define their cyclic cohomology in the spirit of Connes-Moscovici cyclic cohomology for Hopf algebras. Para-Hopf algebroids are closely related to, but different from, Hopf algebroids. Their definition is motivated by attempting to define a cyclic cohomology theory for Hopf algebroids in general. We show that many of Hopf algebraic structures, ...

The goal of our work is to study the spaces of primitive elements of the Hopf algebras associated to the permutahedra and the associahedra. We introduce the notion of shuffle bialgebras, and compute the subpaces of primitive elements associated to these algebras. These spaces of primitive elements have natural structure of some type of algebras which we describe in terms of generators and relat...

We obtain the double factorization of braided bialgebras or braided Hopf algebras, give relation among integrals and semisimplicity of braided Hopf algebra and its factors.