An upper bound for the number of Galois points for a plane curve

Source abstract

A point on a plane curve is said to be Galois (with respect to the curve) if the projection from the point as a map from the curve to a line induces a Galois extension of function fields. It is known that the number of Galois points is finite except for a certain explicit example. We give an upper bound for the number of Galois points for any curve other than the example and describe curves attaining the bound.