canonicalPeriodicDeficitDerivativePackage
plain-language theorem explainer
Packages the canonical deficit-angle directional derivative data on the periodic Freudenthal torus of size (Nx,Ny,Nz). Gravity Track 1.B proofs cite it whenever the Regge first variation must be fixed rather than left abstract. Construction wires the flat local-angle length-chain rule through edge-slot bookkeeping into conformal Schläfli cancellation, then into the deficit package.
Claim. For integers $N_x,N_y,N_z\ge 3$, the canonical encoded periodic Freudenthal torus carries a concrete deficit-angle directional-derivative package on its triangulation $K$: the package is the one induced by conformal Schläfli cancellation from the flat local-angle length-chain rule and the encoded periodic edge-slot incidence bookkeeping.
background
This module does not freely assert the physical Dirichlet equality. It packages the exact obligations needed to instantiate PhysicalSixTetCubicDirichletModel on a periodic Freudenthal torus scaffold.
The underlying complex is the canonical encoded periodic Freudenthal torus: a 3D triangulation $K$ with incidence consistency, built from the endpoint-incidence data of the periodic lattice. Edge-slot bookkeeping records how edges partition into incidence slots on that encoded torus. The local-angle length-chain rule package supplies the flat chain-rule identities relating dihedral angles to edge lengths; the local dihedral derivative package is the first-variation data for those angles.
A deficit-angle directional-derivative package is the structured object that lets one differentiate hinge deficits along vertex potentials. Upstream, conformal Schläfli cancellation is obtained from a length-chain package plus incidence bookkeeping on the dihedral derivatives; that cancellation is the bridge from combinatorial bookkeeping to a well-defined deficit package.
proof idea
Definitional assembly, not a tactic proof. Bind the canonical encoded periodic Freudenthal torus $P$, its local-angle length-chain package $L$, and its local dihedral derivative package $A$. Pass the edge-slot bookkeeping of $P$ into conformal Schläfli incidence bookkeeping (on $A$), feed that with $L$ into conformal Schläfli cancellation from the length chain, and finally apply the constructor that builds a deficit package from conformal Schläfli cancellation. The result is a fully determined DeficitAngleDirectionalDerivativePackage on $P.K$.
why it matters
In the canonical Track 1.B branch the deficit package is no longer an arbitrary hypothesis: it is fixed by the periodic Freudenthal geometry and the flat local-angle chain rule. Downstream, the specialized deficit-derivative evaluation theorem reads derivatives off this package. The main consumers are the local-correspondence endpoints that identify mixed hinge-deficit data with the concrete edge-stencil Dirichlet energy: the strong form (eventual vanishing of weighted deficit derivatives), the weaker stationary-Schläfli forms (with cell-tet or length-chain targets), and the mixed-hinge edge-stencil target built from a local-angle hypothesis. Those endpoints are the remaining obligations toward the physical six-tet cubic Dirichlet model on the periodic lattice, linking discrete Regge first variation to continuum Dirichlet energy in the RS gravity track.
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