canonicalThreshold

The module states a structural RS cosmology package: the cost is $J(x) = \frac12(x + 1/x) - 1$, $\varphi$ is the golden ratio, and spatial dimension $D = 3$ is forced. Imports pull $\varphi$ from Constants and the cost apparatus from Cost.

In the forcing chain, T5 fixes $J$ uniquely and T6 forces $\varphi$ as the self-similar fixed point. Sibling definitions in this file introduce a domain cost and prove it nonnegative; the threshold sits beside those as the comparison level used by the structural certificate.

Numerically $\varphi \approx 1.618$, so the threshold is a small positive real near $0.118$. It is not the Berry creation scale $\varphi^{-1}$; it is a separate cosmology cutoff expressed in RS-native units.

Bare definition: the identifier is bound to the real expression $\varphi - 3/2$. No lemmas, tactics, or rewriting. Downstream positivity (sibling canonicalThreshold_pos) is where any inequality work lives.

Gives the structural module a single named cutoff for domain-cost comparisons and the RS_COS_Structural_001 certificate. The module claims a zero-sorry structural theorem package built on $J$, $\varphi$, and $D = 3$; this constant is the numerical hinge those comparisons use.

It does not itself close a forcing step (T0–T8 already force $\varphi$ and $D$). Its role is local: pin the threshold so certificate inhabitants and nonnegativity lemmas can refer to one symbol rather than an inline expression. No downstream edges are recorded on the page, so its immediate consumers are the sibling positivity and cert constructions in the same file.