Residual Vacuum Stress: From the Cosmological Constant to Relaxation Dynamics

Scientific Brief presenting the core physical and mathematical structure of a residual-vacuum-stress framework. The proposal interprets the cosmological constant as the mature equilibrium limit of a broader vacuum-response sector. Residual relational non-saturation is represented through vacuum porosity, while its possible macroscopic expression is described by a vacuum stress \(S\) and, away from equilibrium, by an additional response tensor \(Q_{\mu\nu}\). The brief also summarises the C3 finite-relaxation closure, its reduced stability domain, the sign-preservation/no-crossing property of the regular branch, and the resulting cosmological consistency tests, including an integral formulation based directly on \(H(z)\). The document is intended as a concise entry point to the associated technical notes and preprint.