Two-cocycles and cleft extensions in left braided categories

Research paper by István Heckenberger, Kevin Wolf

Indexed on: 09 Feb '20Published on: 12 Jun '19Published in: arXiv - Mathematics - Quantum Algebra


We define two-cocycles and cleft extensions in categories that are not necessarily braided, but where specific objects braid from one direction, like for a Hopf algebra $H$ a Yetter-Drinfeld module braids from the left with $H$-modules. We will generalize classical results to this context and give some application for the categories of Yetter-Drinfeld modules and $H$-modules. In particular we will describe liftings of coradically graded Hopf algebras in the category of Yetter-Drinfeld modules with these techniques.