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

Minimal Structural Sufficiency (Fₘᵢₙ) 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 Fₘᵢₙ 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.