I Finding useful denial (1 Viewer)

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Let U be universe under consideration, and let P(x) and Q(x) be predicate with free variable x. Find a useful denial for (∀x∈U)(P(x)⇒Q(x))

Then my answer is:





I'm unsure if I am on the write path when it comes to finding the useful denial, is this how to do it?

Thank you.


Insights Author
2018 Award
Your last step is wrong.
\lnot \,(P(x) \Longrightarrow Q(x)) \Longleftrightarrow \exists \,x_0 \in U \, : \,P(x_0) \wedge \lnot \,Q(x_0)

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