Structural Closure of Cosmological Components\\ in Pre-Geometric Cosmology

We report an explicit finite integral chain-complex realization in which a degree-preserving Z2 symmetry of a precursor complex, under a specified integral regrading, admits an exact filtered continuation rather than a strictly degree-preserving one. The precursor realization has total chain dimension 109, and the regrading preserves this total dimension and the Betti vector while redistributing generators in the acyclic sector.In the distinguished six-dimensional sector of this realization, the relevant integral lift decomposes into five split directions and a single nonsplit rank-two Z[Z2]-block. The associated obstruction is represented by a distinguished exact cycle k*, which is invisible in homology but nontrivial at chain level.After regrading, the nonsplit relation cannot be implemented by a strictly degree-preserving transported involution. It is instead realized by a filtered operator of the formtau_hat = tau_0 + N_{-2},where N_{-2} is a rank-one degree-minus-two chain map. For the explicit realization considered here,tau_hat^2 = I, N_{-2}^2 = 0, {tau_0, N_{-2}} = 0, [d, N_{-2}] = 0,and consequently[d, tau_hat] = 0.The image of N_{-2} is generated by an exact cycle, so N_{-2} induces the zero map on homology. Moreover, the associated graded action of tau_hat coincides with tau_0.Thus the regraded realization exhibits a rank-one filtered Z2 extension that is invisible to ordinary homology while remaining nontrivial at the integral chain level. The result concerns the stated finite realization; no claim is made here that the particular regrading is uniquely or functorially selected among all admissible integral regradings. No physical interpretation, experimental claim, or phenomenological identification is required for the mathematical result reported here.