Entry details for q = 22 = 4, g = 8
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Lower bound Nmin = 22

Submitted by Everett Howe
Date 04-20-2020
Reference Everett W. Howe
The maximum number of points on a curve of genus eight over the field of four elements
J. Number Theory 220 (2021) 320–329
Comments
An example is given by
y^2 + (x^3 + x + 1)y = x^6 + x^5 + x^4 + x^2
z^3 = (x+1)y + x^2

This is a degree-3 Kummer extension of the genus-2 curve defined by the first equation, ramified at 4 points.
Tags Explicit curves

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Upper bound Nmax = 24

Submitted by Everett Howe
Date 04-14-2010
Reference Jean-Pierre Serre
Rational points on curves over finite fields. With contributions by Everett Howe, Joseph Oesterlé and Christophe Ritzenthaler. Edited by Alp Bassa, Elisa Lorenzo García, Christophe Ritzenthaler and René Schoof
Documents Mathématiques 18, Société Mathématique de France, Paris, 2020
Comments
The Oesterlé bound. Here is a real Weil polynomial that we don't know how to eliminate: x * (x + 2)^4 * (x + 3) * (x + 4)^2
Tags Oesterlé bound

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Restrictions on curve     
Everett Howe
05-04-2010 00:36
In fact, the real Weil polynomial listed above is the *only* possibility for a curve with 24 points. Also, if there is a curve with this real Weil polynomial, it must have a degree-3 map to the unique elliptic curve with 8 points.

All this can be deduced from the Magma package IsogenyClasses.magma, found at http://alumnus.caltech.edu/~however/Magma/IsogenyClasses.magma