Relative Homological Algebra

ISBN: 9783110215229 出版年：2011 页码：108 Enochs, Edgar E Jenda, Overtoun M G De Gruyter

We study classes of relative injective and projective comodules and extend well-known results about projective comodules given in [7]. The existence of covers and envelopes by these classes of comodules is also studied and used to characterize the projective dimension of a coalgebra. We also compare this homological coalgebra with the very intensively studied homological algebra of the dual algebra (see [5]).