simp
case left
α : Type
inst✝ : DecidableEq α
σ_0 σ_1 : Type
M_0 : EpsilonNFA α σ_0
M_1 : EpsilonNFA α σ_1
p_0 q_0 : σ_0
xs : List σ_0
a2_left : { start_state := p_0, stop_state_list := xs } ∈ M_0.epsilon_arrow_list
a2_right : q_0 ∈ xs
⊢ { start_state := p_0, stop_state_list := xs } ∈ M_0.epsilon_arrow_list ∧
    { start_state := p_0, stop_state_list := xs }.start_state = p_0 ∧
      List.map Sum.inl { start_state := p_0, stop_state_list := xs }.stop_state_list = List.map Sum.inl xs
case left
α : Type
inst✝ : DecidableEq α
σ_0 σ_1 : Type
M_0 : EpsilonNFA α σ_0
M_1 : EpsilonNFA α σ_1
p_0 q_0 : σ_0
xs : List σ_0
a2_left : { start_state := p_0, stop_state_list := xs } ∈ M_0.epsilon_arrow_list
a2_right : q_0 ∈ xs
⊢ { start_state := p_0, stop_state_list := xs } ∈ M_0.epsilon_arrow_list