edgeVerts
plain-language theorem explainer
Enumerates the 33 distinct undirected edges of the two-cube Freudenthal strip as ordered pairs of the twelve vertices. Anyone working with multi-cube incidence, shared-face deduplication, or local-to-global edge slots cites this table. The body is a pure case split on Fin 33 with an absurdity clause for the impossible residue.
Claim. A map sending each global edge index $e \in \{0,\ldots,32\}$ to an ordered pair of vertices in $\{0,\ldots,11\}$, listing the thirty-three unique edges of the two-cube Freudenthal strip (two unit cubes glued on a square face).
background
The module builds the smallest nontrivial multi-cube Freudenthal example: two unit cubes sharing one square face, each cut into six Freudenthal tetrahedra with matching face triangulation. Vertices are indexed by $V = \mathrm{Fin},12$ (eight corners of the first cube plus four new corners of the second). Edges are indexed by $E = \mathrm{Fin},33$.
The one-cube precursor lists nineteen unique edges on eight vertices. Gluing a second cube adds the new cube's internal edges and the four new outer face edges, while the five shared-face edges are not double-counted, yielding $19 + 19 - 5 = 33$.
This table is the concrete incidence data against which local edge slots inside each tetrahedron are matched after global deduplication.
proof idea
Definition by exhaustive pattern match on the edge index. Cases $0$ through $32$ each return a fixed ordered pair $(i,j)$ of vertex indices. The residual constructor $\langle n+33, h\rangle$ is discharged by absurd plus omega, since no element of $\mathrm{Fin},33$ can satisfy that bound. No lemmas are invoked; the map is pure data.
why it matters
Supplies the global edge list for the first multi-cube incidence instance beyond the single-cube sanity check. Downstream, edgeInTet_vertices and edgeInTet_iff_localEdgeOf use it to prove that every local tetrahedron edge slot lands on one of these thirty-three pairs (up to order). The same table is reused when the strip is viewed as a unit-step graph for rung-descent arguments in cosmology modules. In the broader Recognition geometry stack it is the concrete witness that Freudenthal face-matching survives cube-to-cube gluing, the step needed before any continuum or continuum-limit claim about the lattice.
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