have isLt := nfa.inBounds' target hn
nfa : NFA
pos : String.Pos
next : SparseSet nfa.nodes.size
currentSave : Array (Option String.Pos)
matched : Option (Array (Option String.Pos))
saveSlots : Data.Vec (Array (Option String.Pos)) nfa.nodes.size
target : Fin nfa.nodes.size
stack : Array (StackEntry nfa.nodes.size)
matched' : Option (Array (Option String.Pos))
next' : SparseSet nfa.nodes.size
saveSlots' : Data.Vec (Array (Option String.Pos)) nfa.nodes.size
i : Fin nfa.nodes.size
inv : UpperInvExploreεClosure nfa i target stack
h✝ : target ∉ next
offset✝ target' : ℕ
hn : nfa[↑target] = Node.save offset✝ target'
h :
  (if h : offset✝ < currentSave.size then
      exploreεClosure nfa pos (next.insert target) (currentSave.set ⟨offset✝, ⋯⟩ (some pos)) matched saveSlots
        ⟨target', ⋯⟩ (stack.push (StackEntry.restore currentSave))
    else exploreεClosure nfa pos (next.insert target) currentSave matched saveSlots ⟨target', ⋯⟩ stack) =
    (matched', next', saveSlots')
⊢ UpperBoundεClosure nfa i (next.insert target) next'
nfa : NFA
pos : String.Pos
next : SparseSet nfa.nodes.size
currentSave : Array (Option String.Pos)
matched : Option (Array (Option String.Pos))
saveSlots : Data.Vec (Array (Option String.Pos)) nfa.nodes.size
target : Fin nfa.nodes.size
stack : Array (StackEntry nfa.nodes.size)
matched' : Option (Array (Option String.Pos))
next' : SparseSet nfa.nodes.size
saveSlots' : Data.Vec (Array (Option String.Pos)) nfa.nodes.size
i : Fin nfa.nodes.size
inv : UpperInvExploreεClosure nfa i target stack
h✝ : target ∉ next
offset✝ target' : ℕ
hn : nfa[↑target] = Node.save offset✝ target'
h :
  (if h : offset✝ < currentSave.size then
      exploreεClosure nfa pos (next.insert target) (currentSave.set ⟨offset✝, ⋯⟩ (some pos)) matched saveSlots
        ⟨target', ⋯⟩ (stack.push (StackEntry.restore currentSave))
    else exploreεClosure nfa pos (next.insert target) currentSave matched saveSlots ⟨target', ⋯⟩ stack) =
    (matched', next', saveSlots')
isLt : (Node.save offset✝ target').inBounds nfa.nodes.size
⊢ UpperBoundεClosure nfa i (next.insert target) next'