Stage A admits a point group only when every one of its operators clears the
correlation bar, so admission is a conjunction over an enumerated list: one
operator reading low deletes the group, and the operators that did clear the bar
can then generate a group no candidate names. That is a contradiction in the
operator table, not a low symmetry. The generated group is now offered as a
candidate as well, and judged by the same chi^2, systematic-b, H and
added-operator-R tests as every other; like a widened rung it does not set
chi2_ref and is not a parent, so offering it cannot make another promotion
harder. Exactly the generated group, never a supergroup of it - proposing the
smallest candidate that merely CONTAINS the generated set was measured and
over-calls where only one operator is confirmed.
Measured on a tetragonal crystal recorded in two unequally exposed arcs, where
the search merge is scaled in P1 and no P1 operator ties the two halves
together: the four operators that exchange h and k read 0.11-0.14 against a bar
of 0.30 while the five that do not read 0.28-0.82 and generate all of 422. The
run adopted an orthorhombic subgroup and wrote 0.98 A of unusable data; it now
adopts the tetragonal group and writes 1.51 A at CC1/2 0.96 and 99.7 per cent
completeness.
A measured pseudo-translation on an axial row no longer revokes the screw
deferral by itself. It is already paid for quantitatively - the absent class is
divided by the modulation depth before either the evidence or the violation
count reads it - and revoking the deferral as well charges one measurement
twice, categorically, on an estimate that moves with anything upstream that
changes which reflections enter the cone. Masking a beam-stop arm, 2.3 per cent
of the detector, took one row's depth across the bound and cost an orthorhombic
crystal both of its screws while its zone evidence rose. The per-reflection rate
test keeps the deferral honest where a modulation really does hide a row.
No threshold changed value. Over 146 datasets - 100 open, 32 in-house, 14
private - no row's space group or cell moves except the crystal above.
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