Kind and tag 39 at schema-minor epoch 12, in both unaligned discriminant
spaces. Measure is schema major 0 -- struct_codec! is a plain walk and
TimeAnchor's Codec has no version branching -- so schema_major() gains no arm
and OperationEnvelopeBlock stays at 3.
CreateMeasure is a nested-container mint following CreateStaffInstance, not
G3a's root-level shape: it carries the owning StaffInstanceId beside the
value, and measure_values carries that parent because Measure has no
back-pointer and the graph-removal arm will need it. Append-only, with
referential preconditions on the parent, the signature, and every non-wall-clock
start referent.
The comparable relation is five exact shapes with an identical boundary
selector; ordering across Start/End is unsound while measure length is
unresolved, so it stays unverifiable. Boundary distance needs a musical delta,
which only same-referent same-selector Musical offsets supply. The effective-grid
oracle reconstructs inheritance from metric_grid_chain and meter_change_chain by
write recency -- not by always overlaying per-key on whole-grid -- folds in
prospective overrides, and runs identically in both reduction modes, so an
instance_grid ledger keeps base-free reduction honest.
Three precondition reasons at 16-18. Repairs a live bug found in review: the
materialized-effect decoder stopped at 13, so reasons 14 and 15 already encoded
without decoding, and the generator drawing below(14) could not see them.
Executed against spec/CONTRACT_GENESIS_G3B_MEASURE.md, mutations M1-M33,
M64-M66, M67-M70. text_projection.tex moved into this packet: four tests read
it live, so the companion bump cannot be split from the grammar.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01QjsEnYhm1gPpf6ii2iFxFV
Levi Neuwirth
e64a4b7103