Originally posted by NotLKH
I had thought they were saying:

n(r-1)/4 mod r <> 1
Actually, they are saying that. Well, sorta, only the formula is n(r-1)/q modulo r is NOT congruent to 1.

What's confusing about the first statement is that if I translate the mod statement into "semi-english", I'd read it as (from NotLKH's original image):

"if (x-a)p is congruent to (xp-a), modulo (xr-1,p)"

But it's the ",p" that really throws me for a loop. If it wasn't there, I'd have no problem with the statement.

Destined