case h.e'_4
m n a b c d : ℤ
h₁ : a ≡ b [ZMOD n]
h₂ : c ≡ d [ZMOD n]
⊢ b + d - (a + c) = b - a + (d - c)
m n a b c d : ℤ
h₁ : a ≡ b [ZMOD n]
h₂ : c ≡ d [ZMOD n]
⊢ n ∣ b + d - (a + c)
convert dvd_add h₁.dvd h₂.dvd using 1
no goals
case h.e'_4
m n a b c d : ℤ
h₁ : a ≡ b [ZMOD n]
h₂ : c ≡ d [ZMOD n]
⊢ b + d - (a + c) = b - a + (d - c)
ring