## Kiran S. Kedlaya

For discussing Olympiad Level Number Theory problems
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### Kiran S. Kedlaya

Show that if \$x\$,\$y\$,\$z\$ are all positive integers then \$(xy+1)(yz+1)(zx+1)\$ is a perfect square if and only if \$xy+1\$,\$yz+1\$,\$zx+1\$ are all perfect squares.

*Mahi*
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### Re: Kiran S. Kedlaya

I think no reply is going to be posted. So here is the original proof by Kiran S Kedlaya - http://diendantoanhoc.net/forum/index.p ... ch_id=1088
Seems just too much to me.

Use \$L^AT_EX\$, It makes our work a lot easier!

Masum
Posts: 592
Joined: Tue Dec 07, 2010 1:12 pm

### Re: Kiran S. Kedlaya

*Mahi* wrote:I think no reply is going to be posted.
What was that?
One one thing is neutral in the universe, that is \$0\$.

*Mahi*
Posts: 1175
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### Re: Kiran S. Kedlaya

Masum wrote:
*Mahi* wrote:I think no reply is going to be posted.
What was that?
That was because people browsing the forum gave a little attention to the post + the proof seemed too much high thought.