which can be fit to experimental data with η = 0.500003(23) (corresponding to the Koide relation) and phase δ = 0.2222220(19), which is almost exactly ⁠ 2 / 9 ⁠ . However, the experimental data are in conflict with simultaneous equality of η = ⁠ 1 / 2 ⁠ and δ = ⁠ 2 / 9 ⁠ .