Hopf Algebroid

Some articles on hopf:

Hopf Algebras - Related Concepts
... Graded Hopf algebras are often used in algebraic topology they are the natural algebraic structure on the direct sum of all homology or cohomology groups of an H-space ... Locally compact quantum groups generalize Hopf algebras and carry a topology ... Quasi-Hopf algebras are generalizations of Hopf algebras, where coassociativity only holds up to a twist ...