# When is a given quiver algebra a hopf algebra?

Given a finite dimensional selfinjective quiver algebra A over a finite field (or more generally an arbitrary field). Whats the best way to check if the algebra A has a Hopf algebra structure or not? If we assume the field to be finite it is a finite problem, so there might be some good algorithm? Note that there is a topic with the same question for not necessary finite dimensional algebra. But quiver algebras are much more special and maybe one can find stronger statements. For example the quiver algebra with 1 loop x and relations x^2=0 is a Hopf algebra iff the field has characteristic two. Is there a classification for small dimensions(maybe up to 100) of local finite dimensional (quiver) Hopf algebras?

• The algebra has to be symmetric, and that cuts downs enormously the list of candidates. I doubt there is a classification. – Mariano Suárez-Álvarez Nov 19 '15 at 20:05
• can you give a source that a local quiver algebra that is a hopf algebra, has to be symmetric? its just clear to me that it has to be weakly symmetric. – Mare Nov 19 '15 at 20:43
• I actually meant Frobenius, not symmetric; this follows frorm a theorem of Larson and Sweedler. – Mariano Suárez-Álvarez Nov 19 '15 at 20:52
• ok, this i know. note that i wrote "selfinjective" quiver algebra. this is equivalent to frobenius in case of quiver algebras. – Mare Nov 19 '15 at 20:53
• The paper "Basic Hopf algebras and quantum groups" by Green and Solberg might be helpful. They give some necessary criterias on the underlying quiver in order for the algebra to have a Hopf algebra structure, and also construct some examples of basic Hopf algebras – Sondre Nov 19 '15 at 22:14