Hopf 2-cocycles of type $A_2$

Abstract

We compute the Hopf 2-cocycles involved in the classification of pointed Hopf algebras of diagonal type $A_2$. When the quantum Serre relations are deformed, we characterize those cocycles that can be recovered from Hochschild cohomology, via exponentiation. We identify some hypotheses that allow us to present general formulas that apply in our setting.

21 pages. We improved the exposition to make the paper more self-contained and corrected several typos; the results remain unchanged