Connectivity Maintenance Cost: A Thermodynamic Threshold Model for the Failure Sequence of Sustained Biological Networks, with Application to Neurodegeneration

Version 3: adds Section 3 "Mathematical Formulation" and includes the complete mathematical development as Appendix A within the manuscript (closed-form decay dynamics, hub-first ordering under the measurable joint condition α·γ < 1, selective-failure prediction, hysteresis after edge loss). Strengthened literature grounding (Attwell & Laughlin 2001; Harris et al. 2012; Vaishnavi et al. 2010). Abstract, declarations and falsification conditions updated accordingly.