Very challenging linear algebra problem (prove there exists an infinite number of spe

A matrix which entries from is called "special" if for each the union of the -th row and the -th column contains distinct entries. Prove that there exist no special matrix if . Prove that there exists an infinite number of special matrix.

This has nothing to do with linear algebra.
This was a 1997 IMO problem.

Good memory. (Sun)

You can contemplate its solution here.

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Originally Posted by Krizalid

Good memory. (Sun)

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Thank you. Yes I have good memory.