A note on the saddle conic of quadratic planar differential systems

Driss Boularas (1)

1 XLIM-MATHIS - Mathématiques & Sécurité de l'information

We give some properties of the saddle conic of quadratic differential systems. We also deduce semi-algebraic conditions for the existence of one, two or three saddle points (in terms of affine invariants).

Mots clés: Qualitative theory of differential equations; saddle; node

Domaines: Mathématiques [math]

Driss Boularas. A note on the saddle conic of quadratic planar differential systems. Electronic Journal of Differential Equations, 2000, 2000 (23), pp.1-9. ⟨hal-01315675⟩