# What is the meaning of symmetric modulo?

So I was reading this: http://rjlipton.wordpress.com/2009/04/01/a-new-factoring-algorithm/

and found it saying "symmetic modulo"

So first off: what is " a -special matrix provided the following are true:" (refer to link)

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"$A$ is symmetric modulo $n$" means that $A$ and $A^t$ are congruent modulo $n$.

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does that mean that two numbers $a$ and $b$ are the same after a modulo operation by n? Ex. 23 and 19 are congruent mod 4. Is this what congruent means? Equal remainders after a modulo as I believe is defined here –  Eiyrioü von Kauyf Apr 8 '12 at 20:22
@EiyrioüvonKauyf: Yes, that's right. –  Hans Lundmark Apr 9 '12 at 6:26
Thank you very much. What would be the utility of this though? Number theory and primality are all I can think of. Do you know of any practical applications? –  Eiyrioü von Kauyf Apr 9 '12 at 19:41
Well, apparently it's at least useful for cooking up April Fools' pranks... ;-) –  Hans Lundmark Apr 10 '12 at 7:11
besides April Fools? –  Eiyrioü von Kauyf Apr 10 '12 at 13:51