On canonical ideals, intersection numbers, and Weierstrass points on Gorenstein curves (Q1906650)

The key-result of the paper is the determination of a ``canonical ideal'' for a subset of branches of an arbitrary curve singularity. The authors generalize some results of Gorenstein and Hironaka, proving a formula which relates the conductor ideal at the singularity with the conductor of the branches and apply it to obtain a formula for the conductor of the semigroup of values; they also prove distributive properties for intersection numbers of subset of branches and give interesting examples; moreover they compute the Weierstrass weight of a Gorenstein singularity with an arbitrary number of branches.