Nonetheless, fields which make use of discrete mathematics often give rise to decidable problems which are thought to be considerably more difficult than \(\textbf{NP}\)-complete ones. For recall that it is a consequence of Theorem 3.1 that the classes \(\textbf{EXP}\) and \(\textbf{NEXP}\) (i.e. exponential time and non-deterministic exponential time) both properly extend \(\textbf{P}\). Hence problems complete for these classes can currently be classified as infeasible regardless of how Open Question 1 is resolved. Such problems include several sub-cases of the decision problem for first-order logic (which will be considered in   Section 4.2)   as well as versions of some of the game-theoretic problems considered in this section.[26]