This work introduces a structural reduction framework for the Collatz conjecture based on a 2-adic state automaton. We establish several results independent of orbit convergence, including:- residue-determined valuation structure,- reduction of periodic orbits to state cycles,- a one-step shadowing bound,- and exclusion of resonance classes. These eliminate all sources of periodic behavior within the framework. The Collatz conjecture is reduced to a single remaining obstruction:the boundedness of the sibling-rank spread across refined state fibers. This work does not claim a complete proof. It provides a structural decomposition that transforms the global problem into a local boundedness question.
Kyung-Up Moon (Sun,) studied this question.