simp [node_to_multiset] at *
case dia'
Y : TNode
y : Formula
y_in_Y : y ∈ node_to_multiset Y
α✝ : Program
φ✝ : Formula
Y_in_ress :
  Y ∈
    List.map
      (fun x =>
        match x with
        | (X, o) => (∅, X, Option.map Sum.inr o))
      (unfoldDiamondLoad' α✝ φ✝)
⊢ lmOfFormula y < 1 + lmOfFormula (unload (⌊α✝⌋φ✝))
case dia'
Y : TNode
y : Formula
y_in_Y :
  y ∈
    match Y with
    | (L, R, none) => ↑(L ++ R)
    | (L, R, some (Sum.inl (~'χ))) => ↑(L ++ R) + {~unload χ}
    | (L, R, some (Sum.inr (~'χ))) => ↑(L ++ R) + {~unload χ}
α✝ : Program
φ✝ : Formula
Y_in_ress : ∃ a b, (a, b) ∈ unfoldDiamondLoad' α✝ φ✝ ∧ ([], a, Option.map Sum.inr b) = Y
⊢ lmOfFormula y < 1 + (lmOfProgram α✝ + lmOfFormula φ✝)