mathlib3

5893fbfc - feat(data/polynomial/monic): add two lemmas on degrees of monic polynomials (#11259)

feat(data/polynomial/monic): add two lemmas on degrees of monic polynomials (#11259) This PR is a step in the direction of simplifying #11139. The two lemmas involve computing the degree of a power of monic polynomials. [Zulip](https://leanprover.zulipchat.com/#narrow/stream/144837-PR-reviews/topic/.2311139.20taylor.20sum.20and.20nat_degree_taylor)