At one step of the algorithm the 3B method will determine that there is no solution either by considering the simplification procedures provided by the end-user or by a direct evaluation of the expressions involved in the problem.
As the simplification procedures may be computer intensive you may avoid using them within the 3B method by setting the flag `ALIAS/Use_Simp_3B` to 0. Alternatively you may specify that only some of the simplification procedures are to be used within the 3B method by using the mechanism described in the CatSimp procedure (section 4.4). You may also set `ALIAS/Use_Simp_3B` to 2: in that case if some variable ranges have been improved the algorithm will check if the whole improved set of ranges may not be a solution of the problem by using all available simplification procedures (including the one having a "NO_3B" in CatSimp).
As for the interval evaluation of the expressions involved in the problem some of the procedures proposed in ALIAS-Maple may use the derivatives of the expression to improve the interval evaluation. This may be computer intensive and you may avoid using these derivatives within the 3B method by setting the variable `ALIAS/Grad_3B` to a list with as many elements as number of variables. The values in this list are thresholds for the width of the variable ranges such that the derivatives are not used if at least one range width exceed the value.