C138 — Six source-qualified P6 comparison squares

23 September 2026 · Bounded step 3 of 20 (C136–C155).

All six retained alternate MT Flood start/close pairs yield a source-field-qualified P6 equal-diagonal 17K comparison. They are six endpoint recombinations within one fixed P6 diagonal.

P6's D=5284 BC and reflected X=3709 AD remain fixed. U=8993−M runs from 6348 down to 6343, within the retained cumulative ON field. Both seasonal components use paired coordinates; a Flood close is an event-year state, not an SP-style person companion.

The ordinary Flood column accompanies the alternate column through the existing +190 profile difference; it is not an extra square vertex. No Gear is assigned to U or D: they are cumulative field members. Some newly used field members have no explicit node in the frozen graph. Their field admission and graph representation are separated in C139. These six recombinations are not six independent validations of 17K.

Source and scope control

All numerical bases in this packet stand for paired coordinates: BC base B is (B+1)t/Bn BC; reflected AD base A is AD At/(A+1)n. Thus a cross-Mirror same-season span is B+A, after the civil no-year-zero subtraction. AD stations are reflected source events, not historical AD occurrences. K=529 throughout.

Regular Gears remain restricted to Noah/Shem/Flood. Creation and Conquest are fixed source-field selections. C133–C135 corrections remain controlling. The C127 graph and canonical controls are frozen; source-field admission is distinguished from an existing graph node and from a generated comparison coordinate. No wider N01/N03 expansion or missing N03 Shem join is repaired. Original Reports 01–10 remain previously verified references; interrupted original Reports 11–25 remain unestablished. Check counts are computational assertions, not independent historical witnesses.

Evidence: CERTIFICATE.json; 42 passing assertions in RESULTS.json. The assertion list identifies the actual tests.