aesop
R L : Finset Formula
φ ψ φ' ψ' : Formula
R_cond_in : φ'⋀ψ' ∈ R
α_in_R : φ⋀ψ ∈ R
h✝ : ¬(φ = φ' ∧ ψ = ψ')
⊢ (φ⋀ψ = φ' ∨ φ⋀ψ = ψ' ∨ ¬φ⋀ψ = φ'⋀ψ') ∨ {φ, ψ} ⊆ insert φ' (insert ψ' (R.erase (φ'⋀ψ')))
no goals