have hchar' : (ringChar K : K) = 2 := by simp [h]
K : Type u
inst✝¹ : CommRing K
inst✝ : IsDomain K
e : Model K
h : ringChar K = 2
⊢ c4 e = 0 ↔ e.a1 = 0
K : Type u
inst✝¹ : CommRing K
inst✝ : IsDomain K
e : Model K
h : ringChar K = 2
hchar' : ↑(ringChar K) = 2
⊢ c4 e = 0 ↔ e.a1 = 0