Exercise:

FORALL x(I) [P(OI) x EQUIV FORALL y(I) P y] EQUIV .EXISTS x P x EQUIV FORALL y P y

You may not use ADVICE, but all other rules and commands are allowed.

Only book theorems may be ASSERTed as lemmas without proof.

For a complete list of book theorems, type PROBLEMS.

No more help available. Sorry.

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