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| (1) |
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| (2) |
Perform QE on this formula. We will then investigate the variance of the first operand of the , i.e. varying the assumptions of the in terms of the quantifier free equivalent of the entire formula.
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Produce the QE result corresponding to replacing with . In terms of the original formula with , this will be equivalent to replacing with . We will do this in two steps - with a deletion then an insertion to achieve the replacement.
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| (4) |
Reinstate the disjunction lost as part of the last call but with . Do this via an insertion.
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| (5) |
Overall we see the formula is now false due to the edge case introduced by , which is included as part of the new assumption replacing the old .