Necessity of a testing condition without square roots: absorb with ε = (2B)⁻¹

To show that a bilinear bound implies a testing condition in ℝ≥0∞, state the bound in ε-form, ∑ α_Q a_Q(f) b_Q(g) ≤ ε⁻¹ A ∫f² + ε B ∫g² for all ε, instead of ≤ C‖f‖‖g‖. Then test with f = 1_R and g = Φ, the tested function itself: X = ∫Φ² equals the bilinear form at (1_R, Φ) restricted to Q ⊆ R. With ε = (2B)⁻¹ you get X ≤ 2ABμ(R) + X/2. Absorb with ENNReal.add_le_add_iff_right (X < ∞ because Φ is bounded and supported in R) to get X ≤ 4ABμ(R). No rpow is needed anywhere.