?? graded vsp vs comodule of laurent polynomials ..... ????? ...... ?? just how equivalent are these ??

?? question of which formulation (?? ...) is more "fundamental" ... ??? graded module as graded _by_ abelian gorup, comodule as comodule _of_ hopf algebra .... ????? .... ???? abelian group as more fundamental than hopf algebra here ??? ..... ??? again, questions of "how equivalent ..." .... ???.....

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