This preprint introduces the full 3+1D mathematical foundation of Deterministic Emergent Computing (DER). It develops a deterministic spinor ontology, a Lorentz-invariant evolution equation, and an invariant functional Z(ψ) that constrains all allowed projective outcomes. The model reconstructs the quantum singlet correlation without hidden-variable spaces, without probability distributions, and without Bell-type assumptions. Instead, correlations emerge as deterministic projective shadows of a single spinorial entity. A numerical verification of the structural invariant is provided. This preprint serves as the structural basis for the forthcoming DER-III paper, which will develop the physical interpretation (One-Body Principle) and the experimental bridge.