The Newman Threshold Has a Cubic Local Collision Model but May Be Set at Infinity
In a seam coordinate, the universal collision of two critical-line folds is
For positive , the two folds lie on the seam. At zero they form one cubic critical event. For negative , they leave the seam as a conjugate pair of interior branch points. This supplies the exact local geometry behind the operator's “last-moment split” intuition.
The de Bruijn--Newman theorem gives a threshold for the real-zero phase. RH implies , while Rodgers--Tao proved . Thus RH would put the physical source exactly at the last permitted heat time.
The decisive correction is global: the threshold need not be witnessed by a finite-height cubic collision. A sequence of collisions may escape to spectral infinity. Local fold confinement therefore cannot prove RH without a source-derived no-incoming-index-flux theorem at infinity.
Research packet:
research/grothendieck/the-newman-threshold-has-a-cubic-local-collision-model-but-may-be-set-at-infinity.md
Checker:
research/grothendieck/checkers/check_newman_cubic_fold_transition.py
The dependency-free checker passes 6/6 exact gates.