A screw zone's evidence drops its largest member to defend against one badly-measured
reflection whose sigma lies about it, and such a reflection is by construction weak - a
fraction of the row it sits on. A member that has passed the violation test AND stands
at or above the mean of its row's own present class is a different animal: not a
measurement that moved, but a reflection that is there. Trimming it removed the single
datum that refutes the claim, and the violation-count deferral then read the inflated
evidence to forgive the very violation that had been trimmed out of it.
Nested screw ORDERS are decided entirely on this. 6_1 extinguishes l != 6n and 6_2/6_4
extinguish l != 3n, so the two differ only on l = 3n not 6n. On a hexagonal crystal
whose 00l row holds five present reflections, the strongest of the whole row lay in
that difference: trimmed, 6_1 read the row as perfectly dead and won on the count of
absences alone - nine at 50.6 nats with one violation against seven at 43.3 with none
- and the run reported the wrong screw order with the right one ranked below it. With
the violation left in, 6_1 reads 6.8 and is refused. An independent POINTLESS run on
the same P1 merge puts the 6_1 condition at probability 0.000 and the 3n condition at
0.998.
Trim only among members that are not both flagged present and at full row strength.
Both halves of the condition are needed and the corpus separates them: the reflection
above stands at 1.94 of its row's mean, where two monoclinic crystals whose 0k0 are
genuinely dead carry one violation each at 0.31 and 0.74 of their row - the
mis-measurement the trim exists for, and one that costs a real 2_1 if it stays in.
Zones with no violations are bit-identical, and so is every candidate whose absent
class is clean.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_013nW6FNRP1bBJJ8pfHiByAT