simp only [← a3]
α : Type
inst✝ : DecidableEq α
σ_0 σ_1 : Type
M_0 : EpsilonNFA α σ_0
M_1 : EpsilonNFA α σ_1
p_0 : σ_1
q_0 : ℕ
xs : List (ℕ ⊕ σ_0 ⊕ σ_1)
x : EpsilonArrow σ_1
a1 : x ∈ M_1.epsilon_arrow_list
a2 : x.start_state = p_0
a3 : List.map (Sum.inr ∘ Sum.inr) x.stop_state_list = xs
⊢ Sum.inl q_0 ∉ xs
α : Type
inst✝ : DecidableEq α
σ_0 σ_1 : Type
M_0 : EpsilonNFA α σ_0
M_1 : EpsilonNFA α σ_1
p_0 : σ_1
q_0 : ℕ
xs : List (ℕ ⊕ σ_0 ⊕ σ_1)
x : EpsilonArrow σ_1
a1 : x ∈ M_1.epsilon_arrow_list
a2 : x.start_state = p_0
a3 : List.map (Sum.inr ∘ Sum.inr) x.stop_state_list = xs
⊢ Sum.inl q_0 ∉ List.map (Sum.inr ∘ Sum.inr) x.stop_state_list