证明 2 个公式在某些条件下等价? [英] Prove 2 formulas equivalent under some conditions?

问题描述

如果a == 0，两个公式a1 == a + b 和a1 == b 是等价的.我想用 Z3 python 找到这个必需的条件(a == 0).我写了下面的代码:

Two formulas a1 == a + b and a1 == b are equivalent if a == 0. I want to find this required condition (a == 0) with Z3 python. I wrote the code below:

from z3 import *

def equivalence(F, G):
    s = Solver()
    s.add(Not(F == G))
    r = s.check()
    if r == unsat:
        print 'Equ'
        print s.model()
    else:
        print 'Not Equ'

a, b = BitVecs('a b', 32)

g = True
tmp = BitVec('tmp', 32)
g = And(g, tmp == a)
tmp1 = BitVec('tmp1', 32)
g = And(g, tmp1 == b)
tmp2 = BitVec('tmp2', 32)
g = And(g, tmp2 == (tmp1 + tmp))
a1 = BitVec('a1', 32) 
g = And(g, a1 == tmp2)

f = True
f = And(f, a1 == b)

equivalence(Exists([a], g), f)

然而，上面的代码总是返回 "Not Equ" 作为输出.然后显然我无法将模型 (a === 0) 作为 "f" 和 "g" 的条件等效，

However, the above code always returns "Not Equ" as the output. Then obviously I cannot get the model (a === 0) as the condition for "f" and "g" to be equivalent, either.

知道代码哪里出错了，以及如何修复它吗?非常感谢！

Any idea on where the code is wrong, and how to fix it? Thanks so much!

推荐答案

帖子中的代码与提出的问题不符.在 smt-lib 邮件列表中提出并回答了类似的问题.

The code in the post does not correspond to the question that is asked. A similar question was asked and answered on the smt-lib mailing list.

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