Support and fixed-time algebra for the transition-window flux.
The cutoff inequalities in the ingredient package imply genuine support statements because their lower bounds are nonnegative indicators.
If a large refresh cutoff and a small xi cutoff are both active, the
small cutoff's refresh index is the large cutoff's index.
On any active refresh window, the large-scale average of the pulled-back gradients is exactly the gradient with that window's index.
If all refresh coefficients vanish, the exact Section 3 flux formula
reduces to the molecular matrix. This uses the zetaProd coefficient
and does not require the unmasked small cutoff zetaMK itself to vanish.
The flux vanishes wherever one of the refresh cutoffs is active.
On the complement of the refresh windows the actual flux factor of the transition-window term
is exactly κm I.