Minimum-energy conditions chain conformation

What then is required of a chain to fold reliably Does the chain have a minimum energy state that is much lower in energy than the rest of the unfolded conformations U If so, is this folded state thermodynamically accessible from U at temperatures and other conditions that allow characterization and perhaps function For longer chains capable of many more contacts and potentially tertiary structure, is this transition kinetically accessible Beyond predicting the existence of a folding reaction, what do the... 

In Eq. (16), yci stands for the number of segments of a chain in conformation c located in layer i. The two equations express the obvious conditions that each lattice layer must be occupied and that the total number of chains is constant. The Lagrange multiplier method is used to calculate the minimum free energy subject to the above constraints. By introducing the multipliers at, for each of the constraints given by Eq. (16), and (i for the constraint expressed by Eq. (17), one can write... 

---