We develop efficient methods for deterministic computations with semi-algebraic sets and apply them to the problem of counting points on curves and Abelian varieties over finite fields. For Abelian varieties of dimension g in projective N space over Fq, we improve Pila's result and show that the pro
Counting Points on Curves over Finite Fields
β Scribed by Ming-Deh Huang; Doug Ierardi
- Publisher
- Elsevier Science
- Year
- 1998
- Tongue
- English
- Weight
- 602 KB
- Volume
- 25
- Category
- Article
- ISSN
- 0747-7171
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β¦ Synopsis
We consider the problem of counting the number of points on a plane curve, defined by a homogeneous polynomial F (x, y, z) β Fq[x, y, z], which are rational over a ground field Fq. More precisely, we show that if we are given a projective plane curve C of degree n, and if C has only ordinary multiple points, then one can compute the number of Fq-rational points on C in randomized time (log q) β where β = n O(1) . Since our algorithm actually computes the characteristic polynomial of the Frobenius endomorphism on the Jacobian of C, it follows that we may also compute (1) the number of Fq-rational points on the smooth projective model of C, (2) the number of Fq-rational points on the Jacobian of C, and (3) the number of F q m -rational points on C in any given finite extension F q m of the ground field, each in a similar time bound.
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