In the solution number method, the solutions are selected as a collection of inner and outer solutions. Inner solutions are generated by the solvers in one step. Outer solutions are generated by parametric sweeps wrapping the inner solutions. If there are more than one inner or outer parameter, they are represented and selected as tuples — that is, combinations of values of the different parameters. Depending on the setup of the studies the parameters can be either filled (all combinations) or sparse (a selection of combinations). In the single-selection case the properties used are solnum, t and outersolnum. In the multi-selection case the valid properties are innerinput, solnum, solnumindices, t, outerinput, outersolnum, and outerindices.