Lemma 4.6. Assuming that:

$f_{1}, f_{2}, f_{3} : G \to ℂ$

Then

| T_{3} (f_{1}, f_{2}, f_{3}) | \leq \min_{i \in [3]} ∥ f_{i} ∥_{U^{2} (G)} \cdot \prod_{j \neq i} ∥ f_{j} ∥_{L^{\infty} (G)} .