The number of coincidences of a 
correspondence of value 
on a curve of curve genus 
is given by
 |
Chasles-Cayley-Brill Formula
See also
Zeuthen's TheoremExplore with Wolfram|Alpha
References
Coolidge, J. L. A Treatise on Algebraic Plane Curves. New York: Dover, p. 129, 1959.Referenced on Wolfram|Alpha
Chasles-Cayley-Brill FormulaCite this as:
Weisstein, Eric W. "Chasles-Cayley-Brill Formula." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/Chasles-Cayley-BrillFormula.html