A non-deterministic machine can non-deterministically construct a truth-value assignment for all n propositional variables of a formula in polynomial time.
For in cases where we can compute the values of a function (or decide a problem) uniformly for the class of instances we are concerned with in practice, this is typically so precisely because we have discovered a polynomial time algorithm which can be implemented on current computing hardware (and hence also as a Turing machine). And in instances where we are currently unable to uniformly compute the values of a function (or decide a problem) for all arguments in which we take interest, it is t