  Transient algebra is a multi-valued algebra for hazard detection in gate
circuits. Sequences of alternating 0's and 1's, called transients, represent
signal values, and gates are modeled by extensions of boolean functions to
transients. Formulas for computing the output transient of a gate from the
input transients are known for NOT, AND, OR} and XOR gates and their
complements, but, in general, even the problem of deciding whether the length
of the output transient exceeds a given bound is NP-complete. We propose a
method of evaluating extensions of general boolean functions. We introduce and
study a class of functions with the following property: Instead of evaluating
an extension of a boolean function on a given set of transients, it is possible
to get the same value by using transients derived from the given ones, but
having length at most 3. We prove that all functions of three variables, as
well as certain other functions, have this property, and can be efficiently
evaluated.
