Characterizing the intersection pattern of two conics: a {B}ezoutian-based approach
Résumé
We show how to efficiently detect the type of the intersection of two arbitrary plane conics. The characterization uses geometric predicates of bidegree $(6,6)$ in the two input conics. While we already proved similar results recently, the approach spelled out here attaches geometric meaning to the predicates and brings substantial geometric insight to the characterization problem, which was previously treated purely algebraically. A key tool in the new method is the Bezoutian.