Question

Is there a way to make z3 solver emit “symbolic” solutions? For example, for equation:

1+x=c

the solution is x=c-1, but z3 always emits a specific model, like [c = 0, x = -1]. How to “define” c as a symbolic variable?

Answer 1

Unfortunately, Z3 does not expose this kind of functionality. Although we use solvers internally, they are not exposed in the API. In future versions, we want to expose internal components such as: solver, Grobner bases procedures, etc. In the current version, we have a tactic called solve-eqs (see http://rise4fun.com/Z3Py/tutorial/strategies). It eliminates variables using a generalization of Gaussian elimination. However, this is a preprocessing step, and you do not have any control over which variables are eliminated.