subst c_in
α : Formula
L R : Finset Formula
α_in_L : α ∈ L
c : TNode
φ ψ φ' ψ' : Formula
precond_eq : φ⋀ψ = α
L_cond_in : φ'⋀ψ' ∈ L
c_in : c = (insert φ' (insert ψ' (L.erase (φ'⋀ψ'))), R)
⊢ (α = φ' ∨ α = ψ' ∨ ¬α = φ'⋀ψ') ∨ {φ, ψ} ⊆ insert φ' (insert ψ' (L.erase (φ'⋀ψ')))
α : Formula
L R : Finset Formula
α_in_L : α ∈ L
φ ψ φ' ψ' : Formula
precond_eq : φ⋀ψ = α
L_cond_in : φ'⋀ψ' ∈ L
⊢ (α = φ' ∨ α = ψ' ∨ ¬α = φ'⋀ψ') ∨ {φ, ψ} ⊆ insert φ' (insert ψ' (L.erase (φ'⋀ψ')))