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Question 1: How could I use Z3 Python API in order to add constraints with unique labels? I was trying something like:

... self.solver.add(self.vm[i] >= 0, 'labelIdx'+str(self.idx)) ...

where self.idx is an integer number which increases for each i, but I get:

z3.z3types.Z3Exception: True, False or Z3 Boolean expression expected. Received labelIdx0

Which means that the arguments of add can not be Strings.

Question 2: Function unsat_core() works only with Solver() objects or also with Optimize() ones. Should I set some option before adding the constraints. Apparently, here [1] this is the procedure.

Thanks!

[1] https://rise4fun.com/Z3/smtc_core

Madalina Erascu
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1 Answers1

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For tracking unsat cores, you need to use assert_and_track, see here: https://z3prover.github.io/api/html/classz3py_1_1_solver.html#ad1255f8f9ba8926bb04e1e2ab38c8c15

Optimization and unsat-cores do not work together unfortunately. This was recently raised as an issue, see here: https://github.com/Z3Prover/z3/issues/1577. As I understand it, it is not because it cannot be supported, but rather they haven't implemented it yet. Commenting on that ticket can motivate them to add support!

alias
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