Theorem: SkewPolynomial.toFinsupp_eq_one (SkewPolynomials.lean)

State before:
R : Type u
a✝ b : R
m n : ℕ
inst✝ : Semiring R
φ : R →+* R
p q a : R[X;φ]
⊢ a.toFinsupp = 1 ↔ a = 1
Tactic:
rw [← toFinsupp_one, toFinsupp_inj]
State after:
no goals