mathlib

0830bfd4 - refactor(analysis/analytic/basic): redefine `formal_multilinear_series.radius` (#5349)

refactor(analysis/analytic/basic): redefine `formal_multilinear_series.radius` (#5349) With the new definition, (a) some proofs get much shorter; (b) we don't need `rpow` in `analytic/basic`.