theorem extracted_formal_statement_220.{w, v} {Z : Type w} {ι : Type v} {f : ι → Z → ℝ} [inst : Nonempty ι]
  {V : (Z → ℝ) → ℝ} (hV₀ : ∀ (f : Z → ℝ), V (-f) = -V f) (hV₁ : BddAbove (Set.range fun i => |V (f i)|))
  (hV₁' : BddAbove (Set.range fun i => V (if (↑i.1 == 0) = true then f i.2 else -f i.2))) (i : ι) :
  V (f i) ≤ ⨆ i, V (if (↑i.1 == 0) = true then f i.2 else -f i.2) := sorry

State before:
case a.H.left
Z : Type w
ι : Type v
f : ι → Z → ℝ
inst✝ : Nonempty ι
V : (Z → ℝ) → ℝ
hV₀ : ∀ (f : Z → ℝ), V (-f) = -V f
hV₁ : BddAbove (Set.range fun i => |V (f i)|)
hV₁' : BddAbove (Set.range fun i => V (if (↑i.1 == 0) = true then f i.2 else -f i.2))
i : ι
⊢ V (f i) ≤ ⨆ i, V (if (↑i.1 == 0) = true then f i.2 else -f i.2)

Tactic: exact le_ciSup hV₁' ⟨(0 : Fin 2), i⟩

State after:

Relevant lemmas:
le_ciSup : ∀ {α : Type u_1} {ι : Sort u_4} [inst : ConditionallyCompleteLattice α] {f : ι → α},
  BddAbove (Set.range f) → ∀ (c : ι), f c ≤ iSup f