  In this entry a constrained violation is one in which the unmodified second law is violated, but with some constraint upon the form of the violation so that some form of modified second law may still be possible. An unconstrained violation is one in which all attempts to construct meaningful modifications of the second law are also invalidated. Although this is still ambiguous, there seems general agreement that a cycle which could complete in finite time and with probability one, and have no other effect than to convert a quantity of heat into work, would certainly constitute an unconstrained violation.