mathlib3

0fc7b29e - feat(data/mv_polynomial): stub on invertible elements (#4320)

feat(data/mv_polynomial): stub on invertible elements (#4320) More from the Witt vector branch. Co-authored-by: Johan Commelin <johan@commelin.net> Co-authored-by: Rob Lewis <rob.y.lewis@gmail.com> Co-authored-by: Johan Commelin <johan@commelin.net>