Puberty onset is a discontinuous spinodal crossing (T5)

Puberty onset is a discontinuous spinodal crossing, not a gradual ramp. As a slow maturation drive rises past the spinodal (h=0.389 ≈ 1.01× h_sp) the pulse-enable gate jumps from OFF (state -0.514) to ON (0.442) in a single step (jump size 0.955). The mechanism and order are sim-verified; chronological age is open.

The juvenile pause is the GnRH oscillator held in the R19 OFF basin. Ramping a maturation drive from zero, the pulse-enable gate stays off until the spinodal 0.3849, then jumps by 0.955 (state -0.514 → 0.442) localised at 1.01× the spinodal. Onset is therefore a threshold crossing, not a smooth rise.

The juvenile pause is an OFF basin

Before puberty the GnRH oscillator is not weak — it is held in the R19 OFF basin, silenced. Puberty is the same switch crossing its spinodal as a slow maturational drive rises, so the question is whether onset is gradual or discontinuous.

Onset is a single discontinuous jump

Ramping the drive slowly from zero, the pulse-enable state stays in the OFF basin (negative) until the drive reaches the spinodal, then jumps to the ON basin (positive) in one step. The jump of 0.955 takes the state from -0.514 to 0.442, localised at 1.01× the spinodal 0.3849.

This is the discriminant: a gradual-maturation model predicts a smooth amplitude ramp, whereas the substrate predicts a threshold crossing. The same threshold, crossed early or not yet, gives central precocious puberty and delayed puberty respectively (§10).

The model fixes the discontinuous order (OFF below → ON above) and the jump/spinodal ratio [V]; mapping the crossing to a calendar age needs external endocrine calibration and is left open [O].