If the total group of the canonical series is divided into two parts, the difference between the number of points in each part and the double of the dimension of the complete series to which it belongs is the same.
Brill-Noether Theorem
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References
Coolidge, J. L. A Treatise on Algebraic Plane Curves. New York: Dover, p. 263, 1959.Referenced on Wolfram|Alpha
Brill-Noether TheoremCite this as:
Weisstein, Eric W. "Brill-Noether Theorem." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/Brill-NoetherTheorem.html