Question

With the z3/python web interface, if I ask:

x = Real ('x')
solve(x * x == 2, show=True)

I nicely get:

Problem:
[x·x = 2]
Solution:
[x = -1.4142135623?]

I thought the following smt-lib2 script would have the same solution:

(set-option :produce-models true)
(declare-fun s0 () Real)
(assert (= 2.0 (* s0 s0)))
(check-sat)

Alas, I get unknown with z3 (v3.2).

I suspect the problem is with the non-linear term (* s0 s0), which the python interface somehow doesn’t suffer from. Is there a way to code the same in smt-lib2 to get a model?

Answer 1

Try your example with Z3 web interface, I get a result of sat.

Z3 web interface and Z3Py are based on Z3 v4.0, so I think the problem is fixed in the upcoming release.