add lemma power_Suc2; generalize power_minus from class comm_ring_1 to ring_1
add lemma power_Suc2; generalize power_minus from class comm_ring_1 to ring_1

MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle