VASTIS 3.0 is a formal system describing the dynamics of evolving possibility spaces under irreversible selection. The framework defines reality as the result of recursive selection processes acting on structured possibility spaces. Structural openness is captured through the measure V(t) := |M_t|, representing the number of functionally viable alternatives. The system integrates:- a minimal dynamical model,- a formalization of irreversibility,- a structural theory of possibility spaces,- and a framework for inter-system coupling. This release (3.0) marks the first stable version of the system. Included:- CORE system (MASTER 3.0)- Foundation layer- Mechanism layer- Emergence / Simulation layer- Meta / Form invariance layer All documents are derived from the same underlying system but address different analytical levels.