The core mathematical structure of the Coordinate-Projection Unified Spacetime Theory (TFT) implicitly contains a set of rigorously derivable biaxial spacetime physical images. Based on the TFT axiom system and field equations, this paper clarifies that the particle spatial motion velocity and the intrinsic time sequence rate induced by mass density are two orthogonal spacetime axes. It demonstrates that the phase space area formed by the coupling of the two axes is the complete existence property of particles. Furthermore, through the biaxial projection geometry framework, the logical unification of the intrinsic existence properties of particles and the classical relativity principle is realized, resolving the theoretical doubts brought by the relativity of velocity and the equivalence between uniform motion and relative rest. Meanwhile, it explains the essential difference in existence between massive particles and photons, and consolidates the unified interpretation foundation of TFT for motion effects, gravitational effects, and observer properties.
Huowang Huang (Thu,) studied this question.