When Formalisms Stop Recovering: Minimal Structural Sufficiency and the Measurement Boundary in Quantum Mechanics

Minimal Structural Sufficiency (F_{min}) defines the formal boundary where unitary evolution in quantum mechanics ends and measurement begins. This study proves that wave function collapse is a structural phase transition rather than a dynamical process. Once the interaction crosses the F_{min} threshold—due to irreversibility or informational constraints—the Schrödinger formalism becomes insufficient. Because this transition is structural and non-distributive, the prior superposition is unitarily unrecoverable. The research demonstrates that "collapse" is the logical consequence of a formalism reaching its limit of structural sufficiency, rather than a failure of the theory itself.