spatial_dim
plain-language theorem explainer
The spatial dimension count is fixed at three by direct reference to the upstream forcing result. Researchers assembling the emergent Lorentzian metric from J-cost minimization would cite this when counting positive eigenvalues. The definition is a one-line abbreviation of the D_physical constant.
Claim. The number of spatial dimensions equals 3, the value forced by the T8 step of the Recognition Science chain.
background
The Spacetime Emergence module derives the full 4D Lorentzian structure from the J-cost functional and the T0-T8 forcing chain. Its opening statement records that one temporal direction arises from the eight-tick octave while three spatial directions arise from T8, yielding the metric signature diag(−1,+1,+1,+1). D_physical is the upstream definition that supplies the integer 3 and carries the annotation that it is RS-compatible.
proof idea
This is a one-line definition that directly equates the name to the upstream D_physical constant.
why it matters
The definition supplies the spatial count required by lorentzian_signature (SE-004), signature_unique (SE-010), spacetime_dim, and octave_matches_spatial. It implements the T8 landmark that forces D = 3 spatial dimensions and thereby closes the spatial half of the derivation chain that produces the Lorentzian metric from RCL and J-uniqueness.
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