Algebras and modules
Model category presentations
Geometry on formal duals of algebras
A comodule is to a comonoid as a module is to a monoid. Where a module is equipped with an action, a comodule is dually equipped with a coaction.
Given a comonoid with comultiplication and counit in a monoidal category , and an object in , a left -coaction is
In some monoidal categories, e.g. of (super)vector spaces, and of Hilbert spaces, one often says (left/right) corepresentation instead of (left/right) coaction.
Revised on November 15, 2013 06:15:09
by Urs Schreiber