constructor
case left
a b c : ↑VeryDiv
⊢ (↑a ∣ ↑b → ↑b ∣ ↑c → ↑a ∣ ↑c) ∧ (↑a ∣ ↑b → ↑b ∣ ↑a → a = b)
case left.left
a b c : ↑VeryDiv
⊢ ↑a ∣ ↑b → ↑b ∣ ↑c → ↑a ∣ ↑c

case left.right
a b c : ↑VeryDiv
⊢ ↑a ∣ ↑b → ↑b ∣ ↑a → a = b