Prof. J. E. Cremona on Wed, 02 Jun 2004 13:20:37 +0200

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Re: Elliptic curves over finite fields

If ap = ellap(E,p) is the Trace of Frobenius at p then

apr = trace(Mod(x,x^2-ap*x+p)^r)  is the trace of Frobenius^r

and so the number you want is 1+p^r-apr.

John Cremona
 Prof. J. E. Cremona             |
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