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IndisputableMonolith.Gravity.SevenGaps.CausalSimplexWick

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Catalogues the two causal tetrahedron types of 3d causal dynamical triangulations between adjacent time slices: (3,1) with three vertices on slice t and one on t+1, and (2,2) with two on each. Supplies slice membership, timelike/spacelike edge predicates, and edge-count identities under a Lorentzian squared-length signature. Gravity and CDT workers cite it when wiring combinatorial carriers to Regge edge data. The body is definitional enumeration plus elementary counting equalities.

claimIn 3d CDT, a causal tetrahedron between adjacent slices is either of type $(3,1)$ (three vertices on slice $t$, one on $t+1$; time reflection $(1,3)$ shares the same edge data) or of type $(2,2)$ (two vertices on each slice). For each type one records slice membership of vertices, which edges are timelike versus spacelike under a Lorentzian squared-length assignment, and the resulting timelike and spacelike edge counts.

background

Causal dynamical triangulations (CDT) build Lorentzian path integrals from piecewise-flat simplicial manifolds with a preferred foliation by discrete time slices. In three dimensions the elementary building blocks between consecutive slices are tetrahedra whose vertices lie on at most two adjacent slices. Only two combinatorial types appear: $(3,1)$ (and its time reflection $(1,3)$) and $(2,2)$.

The module sits inside the SevenGaps gravity campaign and imports the Cayley-Menger / Regge stack (CayleyMengerPolynomial, DihedralCayleyMenger, ReggeRigorousFoundation). Those modules supply the Euclidean squared-edge polynomial and dihedral cosines needed later to compare Regge second-variation coefficients to face areas. Here the focus is purely causal and combinatorial: which edges cross the slice and which stay inside it, once a Lorentzian sign pattern is chosen on squared lengths.

Sibling definitions introduce an inductive type of causal tetrahedra, a slice-membership map, a timelike predicate, and explicit counts of timelike versus spacelike edges for each type, together with a Lorentzian squared-edge assignment.

proof idea

This is primarily a definition module. CausalTetType enumerates the two CDT tetrahedron classes. sliceOf and isTimelike are pure data and predicates on vertices and edges. The equalities isTimelike_threeOne_eq_crossSlice and isTimelike_twoTwo_eq_crossSlice identify the timelike edges with the cross-slice edges by case analysis on the type. The remaining declarations are arithmetic identities: how many edges lie in each slice and how many are timelike or spacelike for $(3,1)$ and $(2,2)$, obtained by direct counting under the fixed Lorentzian squared-edge pattern lorentzianSqEdges. No deep analytic argument is required.

why it matters in Recognition Science

The SevenGaps campaign tracks scoped quantum-gravity increments that are not yet full-strength closures. This module supplies the causal simplex vocabulary that downstream ledgers and blockers import. CampaignLedger records machine-checked status of each gap and pulls this file as part of the combinatorial carrier layer. MetricRefinementCarrierBlocker uses the same stack to certify a P2.5 obstruction: path-sum measures and triangulation classes only see cardinalities and incidence, not metric geometries, so distinct positive edge-length assignments on a one-tetrahedron complex remain unidentified.

In the broader Recognition gravity program the file bridges discrete causal structure to the Regge foundation (Cayley-Menger polynomials and dihedral cofactors) that aims at the component identity $M_{ij}=-\mathrm{area}(f_{ij})$. It does not itself close that identity; it fixes the Lorentzian edge typing against which metric refinement and second-variation comparisons are later stated.

scope and limits

used by (2)

From the project-wide theorem graph. These declarations reference this one in their body.

depends on (3)

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declarations in this module (50)