∀ {Γ : Type u_1} {Λ : Type u_2} {σ : Type u_3} [inst : Inhabited Λ] [inst_1 : Inhabited Γ]
  (M : Λ → Turing.TM1.Stmt Γ Λ σ) {S : Finset Λ},
  Turing.TM1.Supports M S →
    ∀ {c c' : Turing.TM1.Cfg Γ Λ σ}, c' ∈ Turing.TM1.step M c → c.l ∈ Finset.insertNone S → c'.l ∈ Finset.insertNone S