rcases h with ⟨h_w, h_h₁, h_h₂⟩
case mp
R : Type u_1
ι : Type u_2
inst✝ : CommSemiring R
p : MvPolynomial ι R
h : ∃ d, coeff d p ≠ 0 ∧ (weightedDegree 1) d ≠ p.totalDegree
⊢ p.leadingTerms ≠ p
case mp.intro.intro
R : Type u_1
ι : Type u_2
inst✝ : CommSemiring R
p : MvPolynomial ι R
h_w : ι →₀ ℕ
h_h₁ : coeff h_w p ≠ 0
h_h₂ : (weightedDegree 1) h_w ≠ p.totalDegree
⊢ p.leadingTerms ≠ p