Multiplication alteration by two-cocycles for bialgebras with weak antipode

Abstract

In this paper we introduce the theory of multiplication alteration by two-cocycles for bialgebras with weakantipode. Moreover, by the connection between two-cocycles and invertible skew pairings, we show that a special caseof the double cross product of these bialgebras can be obtained as a deformation of a bialgebra with weak antipode.