# V16 Temporal Decay in SPH Transport Equation

## Core Formula Extension
delta_STI(i→j) = W(dist, h_i) * g_eff(e_ij) * gate(e_ij) * (STI_j - STI_i + alpha*(U_j - U_i))

where g_eff(e_ij) = g(e_ij) * exp(-lambda * staleness_ij)

## Interpretation
- Fresh high-conductance edge (staleness=0): g_eff = g (full permeability)
- Stale high-conductance edge (staleness=10, lambda=0.1): g_eff = 0.368*g (63% reduction)
- Ancient edge (staleness=30, lambda=0.1): g_eff = 0.050*g (95% reduction, near-zero flow)

## Interaction with Other Layers
- SPH kernel W(dist,h): spatial locality unchanged
- Conductance g: reward+hebb+info_gain as before, BUT now time-modulated
- Gate: contradiction veto unchanged (binary)
- Utility U: directional pull unchanged

## Key Design Choice
Decay applies to CONDUCTANCE (permeability), not to STI directly.
STI decays via ECAN rent. Conductance decays via staleness.
Two independent decay channels: attention fades (rent), evidence ages (staleness).

## Validated by v14a+v15
- v14a: revision alone cannot reduce confidence (monotonic rise)
- v15: pre-inference discounting drops result conf 41% at aggressive decay
- v16: decay lives in transport equation conductance term