Coquasitriangularity is dual property to quasitriangularity.
A -bialgebra (or, in particular, Hopf algebra) is coquasitriangular (or dual quasitriangular) if it is equipped with a -linear map which is invertible in convolution algebra (with respect to the convolution-unit ) with a convolution inverse denoted such that the opposite multiplication is given by
and the following two identities hold when applied on :
with the subscript notation as explained in the lab entry quasitriangular Hopf algebra. The main examples come from quantized function algebras (that is, roughly, dual of quantized enveloping algebras).