Severi Strata of Plane Curve Singularities
摘要
Examples of algebraic curves with singularities are known since antiquity. The cubic curve called the cissoid of Diocles, that was used to solve the Delian problem, exhibits a proud cusp at its origin. The conchoid of Nicomedes, used for the trisection of an arbitrary angle, contains a node or a cusp, depending on the value of a parameter.