Commit 2022-03-28 11:38 c0421e76

feat({ring_theory,group_theory}/localization): add some small lemmas for localisation API (#12861) Add the following:

• sub_mk: a/b - c/d = (ad - bc)/(bd)
• mk_pow: (a/b)^n = a^n/b^n
• mk_int_cast, mk_nat_cast: m = m/1 for integer/natural number m.