The variable or list of variables Ints will be considered integers when solving the problem associated with BfsInstance. Note that this does not mean that they will be treated as integers by the specified node relaxation solver, rather that they will be considered as candidates for branching decisions in nodes where their solution value is not integral (to within a tolerance parameter set in the options list of BfsInstance:solver_setup/3). The predefined node separation schemes will branch on these variables. User-defined node separation predicates may access the fractional variables at the current node via a call to BfsInstance:get/2