Proposition 2.8 Let H be a Hopf algebra and U a subHopfalgebra of H0 such that both H and U have bijective antipodes, and assume that U satisfies the RL-condition with respect to H. Let A be a U-comodule algebra, so that A is an H-module algebra as above.

• 命题2.；8 H是一个Hopf代数，U是H~0的一个子Hopf代数使得H和U有双射的对极，假定U关于H满足RL-条件。 如上所述，A是一个U-余模代数，使得A是一个H-模代数。