e_220313
plain-language theorem explainer
For multi-index (2,2,0,3,1,3) on Fin 4, the folded numerator coupling m2Num equals eight times the explicit kernel value explicitZ. Gravity analysts cite it when discharging one cell of the 4D Regge midpoint M2–TT identity. The proof is a single kernel decide on two closed integer expressions.
Claim. For indices $a{=}2,\,b{=}2,\,c{=}0,\,d{=}3,\,i{=}1,\,j{=}3$ in $\mathrm{Fin}\,4$, the folded numerator coupling equals eight times the explicit integer kernel: $\mathrm{m2Num}(2,2,0,3,1,3)=8\cdot\mathrm{explicitZ}(2,2,0,3,1,3)$.
background
This module sits in the 4D Regge midpoint analysis of the M2–TT identity. The local goal, stated in the module doc, is to certify $\mathrm{m2Num}=8\cdot\mathrm{explicitZ}$ cell by cell across the $4^6$ index space, in chunks of kernel decides.
$\mathrm{m2Num}(a,b,c,d,i,j)$ is the integer obtained by folding a fixed coupling list and summing each term's contribution at those six indices. $\mathrm{explicitZ}$ is the matching closed-form integer table on the same six $\mathrm{Fin},4$ arguments (sparse nonzero pattern such as $4$, $-2$, etc. on selected index tuples).
Chunk 10 supplies one block of those pointwise equalities; the present declaration is the cell at $(2,2,0,3,1,3)$.
proof idea
One-line proof by decide. Both sides reduce to concrete integers once the six Fin-4 indices are fixed: the left via the fold definition of the numerator coupling, the right via the pattern-match table for the explicit kernel. The kernel checks integer equality; no algebraic rewriting or external lemmas are invoked.
why it matters
Parent consumer is $\mathrm{m2Num_eq_eight_explicitZ}$, which states the identity for all $a,b,c,d,i,j:\mathrm{Fin},4$ and discharges it by exhaustive fin_cases. Each chunk theorem such as this one fills one case of that assembly.
In the Recognition gravity stack this is bookkeeping infrastructure for the exact midpoint M2–TT identity in 4D Regge calculus, not a new physical law. It supports the discrete curvature/coupling identities that feed continuum matching, rather than the T0–T8 forcing chain or the J-cost uniqueness step directly.
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