generalize h : [] = cs at path
i i' : ℕ
nfa : NFA
start : ℕ
path : nfa.pathIn start i i' []
⊢ i' ∈ nfa.εClosure i
i i' : ℕ
nfa : NFA
start : ℕ
cs : List Char
h : [] = cs
path : nfa.pathIn start i i' cs
⊢ i' ∈ nfa.εClosure i