The Time-Symmetric Parity Constraint or The Twin-Time Theory of Cosmology

Summary description — 

This compendium brings together the complete sequence of papers defining the Time-Symmetric Parity Constraint (TSPC): a geometric framework in which the universe’s observed anomalies are re-expressed as structural consequences of a fixed algebraic condition on the spacetime metric.

TSPC imposes a parity constraint that forbids geometries with an absolute direction of time, requiring mirrored temporal domains evolving from a shared low-entropy origin. Without adding new fields or particles, the condition modifies curvature coupling through a single bounded parameter α_λ. The suite traces the resulting implications for late-time acceleration, dark matter, inflation, entropy symmetry, and the correlated H₀ and S₈ tensions. It extends to empirical tests in lensing, gravitational-wave populations, and sky-wide dipoles.

Together these papers form a single argument: that geometry and baryonic matter alone account for the phenomena attributed to the dark sector. The hypothesis is parsimonious, coherent, and falsifiable; if any of the correlated signatures fail, the framework is excluded.

Three supplements have been added in response to recent research:

(1) a comment on the interpretation of the recently reported γ-ray excess from the Galactic Centre (Paper 14);

(2) a review of the new analysis of the radial-acceleration relation in extremely low-mass dwarf galaxies (Paper 15); and

(3) a comparative analysis of several recent interpretations of the DESI DR2 data (Paper 16).

Substantive updates — 

v7 (2025-11-26).  New paper 17 added: Undressing the Emperor - A historical and conceptual dismantling of the FRW ansatz, with consequential amendments to the Preface and the Introduction.

v.9 (2025-11-27) - Corrections to Paper 14: The Galactic-Centre Gamma Excess Reconsidered, clarifying the findings of Muru et al. (2025) on the morphology of the Galactic-centre γ-ray excess, together with the addition of a footnote noting recent claims by Tomonori Totani (2025) of a high-latitude annihilation signal. Explaining why these claims do not affect the analysis presented.

v.10  (2025-12-04) Paper 2, Sections 2–3 updated to state Π as fixed and primitive, and to clarify the resulting exclusions for admissible metrics (e.g. Gödel, anisotropic cases).

v.11 (2025-12-05) Paper 8 udated with ACT DR6 constraints on early-Universe models; Paper 14 adds recent mid-IR flare and extinction results, further tightening the astrophysical interpretation of the Galactic-Centre excess. No changes have been made to the core TSPC framework.

v.13 (2025-12-11) Minor revisions: added rebuttal of the ΛCDM timing argument in Paper 9 and clarified the Bullet Cluster discussion in Paper 10, removing dark-halo assumptions.

(v.14  Formatting corrections)