have hchar'' : (3 : K) = 0 := by simp [← hchar', ringChar.Nat.cast_ringChar]
K : Type u
inst✝¹ : CommRing K
inst✝ : IsDomain K
e : Model K
h : ringChar K = 3
hdisc : discr e = 0
hb2 : b2 e = 0
hchar' : ↑(ringChar K) = 3
⊢ b4 e = 0
K : Type u
inst✝¹ : CommRing K
inst✝ : IsDomain K
e : Model K
h : ringChar K = 3
hdisc : discr e = 0
hb2 : b2 e = 0
hchar' : ↑(ringChar K) = 3
hchar'' : 3 = 0
⊢ b4 e = 0