intro h
case mp
f g : Vars →₀ ℕ
⊢ (∀ (x : Vars), f x = g x) → f α = g α ∧ f β = g β ∧ f γ = g γ ∧ f δ = g δ
case mp
f g : Vars →₀ ℕ
h : ∀ (x : Vars), f x = g x
⊢ f α = g α ∧ f β = g β ∧ f γ = g γ ∧ f δ = g δ