The order in which quantifiers appear is very important; it must be maintained when converting a formula to prenex normal form.
Consider the ambiguous sentence, ``Every man loves some woman.'' This sentence could be interpreted as:
&forall x [Man(x) &rarr &exist y [Woman(y) &and Loves(x,y)]]
and Skolemized:
Man(x) &rarr
[Woman(lover(x)) &and Loves(x,lover(x))]
&exist y &forall x [Man(x) &rarr [Woman(y) &and Loves(x,y)]]
and Skolemized:
Man(x) &rarr [Woman(a) &and Loves(x,a)]
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