This figure is interactive and needs JavaScript. The underlying mathematics is given in full in the text: the Fourier parameterization (Equation 3), the coefficient vector (Equation 4), the output bound (Equation 5) and the GELU-based initialization (Equations 6–7), with the learned seed-1 coefficients reported in Section 4.1.
FAct is periodic with period 2π; it is drawn over one period here. GELU is shown as a non-periodic reference, so the two curves may diverge near ±π — this is inherent to a truncated Fourier series, not an approximation error.