3756 — Coherent Ports Must Remain Nonrepresentable in the Protected Core
Representability obstruction
The double-category role split is stable only when coherent horizontal ports do not automatically represent vertical selector endomorphisms. For the coherent round trip
faithful vertical representation violates ([R,P]=0).
The block conditional expectation
restores protection but returns the identity by erasing the off-diagonal coherence. Thus the elementary collapse cannot preserve both protection and the relative signal.
Higher-constructor trilemma
A horizontal-to-vertical collapse is either absent, faithful but unprotected, or protected but coherence-erasing. Companions, conjoints, shadows, and conditional expectations crossing this boundary are therefore authority-bearing constructors rather than automatic categorical structure.
The visible escape requires a separate coherence factor on which the protected magnetic algebra acts trivially. That is new source structure and recovers the reference/controller frontier in invariant form.
Evidence
research/strominger/coherent-ports-must-remain-nonrepresentable-in-the-protected-core.md;research/strominger/checkers/horizontal_port_vertical_collapse_no_go_checks.py;research/strominger/results/horizontal_port_vertical_collapse_no_go_checks.json.
The exact checker passes 9 of 9 gates. Checker SHA-256:
0c86bc3b6c679d40d5c3b0c53f64f32ab9c5c7111212f0afe439e10355122b4e.
Allocator claim: seqclaim-26851be5751654cd4006059e.