Chirality from Torsion and Immersion in Geometric Unity
In Geometric Unity (GU), chirality is not fundamental on the ambient space $Y$. It emerges on the observed $4$-manifold $X$ from three intertwined ingredients: (i) an immersion (observation map) $\iota: X \hookrightarrow Y$ and pullback of fields, (ii) a gauge-equivariant torsion that generates a $\gamma_5$ coupling, and (iii) the signature/orientation data that fixes which chirality survives upon pullback.
