914 — The Three-Normal Associated-Grade Line Is Dihedrally Untwisted
Reflection gate
Entries 912–913 construct a rank-one first third-normal grade and prove its trivial cyclic character. To determine the full stabilizer representation, freeze the reflection
It transports the labelled maximal flag by
Four possible signs are retained independently.
Basis variances
The dense-right source block transforms as
which is the reversed (C_0) basis. The sparse-right block likewise transforms as
again reversed relative to (C_0). Hence
and their matrix-variance contribution is (+1).
Residue and conormal orientations
The reflection preserves the ordered normal slots:
It does not permute the positions of the one-, two-, and three-particle normals. Thus the ordered residue orientation contributes (+1).
The first-grade generator transforms literally:
without inversion or rescaling, so the conormal character is also (+1).
Result
The complete filtered reflection character is
Combining this with Entry 913 gives
The first three-normal string class is therefore globally occurrence-covariant over this maximal-flag orbit, not merely cyclically covariant.
Scope and next falsifier
This closes the symmetry character of one rank-one maximal-flag class. It does not determine whether all maximal six-point flags yield the same filtered rank. The next test is an orbit census of maximal compatible channel triples, followed by one exact representative calculation per (D_3)-orbit. A rank jump would falsify uniformity of the local coefficient packet without requiring a new carrier.