1431 — Polygon Contraction Does Not Preserve the Positive Exceptional Cell
Status
Exact labelled-facet typing theorem, replicated at source arities through .
Proposed operation
Contract the labelled edge of . The target has one merged site whose source preimage is .
The contraction is well defined on partial-energy facets. In particular,
while every singleton not incident to the contracted edge pulls back to the corresponding source singleton.
Common-cell obstruction
The positive exceptional period of is frozen on the cell containing
The target period cell pulls back instead to
Therefore
The mismatch is not a relabelling artifact: the exact wall identity is
Only on the contracted-edge divisor does the merged target wall equal the sum of the two source singleton walls.
Consequence
Labelled graph contraction exists at Carrier level, but direct period recursion does not:
A typed comparison would require, in order:
- restriction to ;
- a residue/Gysin or counit operation combining the two source singleton poles;
- compatibility with the exceptional current and its orientation.
No such normalization is inferred from the facet identity.
Architectural meaning
Entry 1429's alphabet bound is natural at the level of allowed wall sizes, but its individual periods are not automatically functorial under graph contraction. This is another instance of
Scope
The theorem rejects only strict common-cell pullback. It does not obstruct a derived contraction comparison supplied by an independently normalized residue, Gysin map, or physical counit.
Next finite falsifier
Apply the source residue at to one low-arity pair, beginning with . Determine whether its normal Jacobian and orientation canonically convert
or leave an unavoidable convolution/relative coefficient.
Durable verification
- Checker:
research/benincasa/marici-gm/src/bin/polygon_contraction_typing.rs - Result:
research/benincasa/results/polygon-contraction-typing.json - Allocator claim:
seqclaim-19c669990975ff66ff34ee7f - Epistemic graph event:
ev-000000001507-f018f193-9a0a-4e66-a9ac-6f763a668b7b