very basic predicate logic question (need help)

just going through some past papers before my exam today and stumbled across this question (see attachment)..

anyone know how i go about answering it? do i just say x = .... y = ....? can someone give me an example answer to this question?

cheers for any help/advice!

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Reply 1

Smaug123

Original post by compSciIsGhey

You can't assign x in the first instance, because it says "for all x…", not "exists x". The question is asking you to find a statement P such that "For all x there exists a y such that P" is different to "There exists a y such that for all x, P", where x and y are married people. Your answer could look like:
"Such a statement P is ____, because it is true that for all married people x there is a married person y such that ____, but it could be false that there exists a married person y such that for all married people x, _____".
That formulation should be a lot easier to answer; humans aren't great at symbolic logic, but we're much better at concrete stuff, so you should work out what a question is actually asking if you get stuck.