mathlib

e186fbb7 - feat(data/mv_polynomial): coeff_mul (#1216)

feat(data/mv_polynomial): coeff_mul (#1216) * feat(data/mv_polynomial): coeff_mul * refactor(data/multiset): rename diagonal to antidiagonal * Rename diagonal to antidiagonal * Define antidiagonal as to_finsupp instead of to_finset * Add docstrings * fix build * Fix build