If a Real curve has no singularities except nodes and Cusps, Bitangents, and
Inflection Points, then
where is the order, is the number of conjugate tangents, is the number of Real
inflections, is the class, is the number of Real conjugate points, and is the
number of Real Cusps. This is also called Klein's Theorem.
See also Plücker's Equation
References
Coolidge, J. L. A Treatise on Algebraic Plane Curves. New York: Dover, p. 114, 1959.
© 1996-9 Eric W. Weisstein
1999-05-26