The problem of a center “in the large” for a general quadratic system

Driss Boularas (1) , Nicolae Vulpe , Constantin Sergeivitch Sibirskii

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

The authors give the necessary and sufficient conditions for the quadratic differential systems to possess two centers. Moreover, the condions are expressed with affine invariants.

Mots clés: quadratic differential systems; centre-focus problem; qualitative theory of differential systems

Domaines: Mathématiques [math]

Driss Boularas, Nicolae Vulpe, Constantin Sergeivitch Sibirskii. The problem of a center “in the large” for a general quadratic system. Доклады Академии Наук / Doklady Mathematics, 1990, 41 (2), pp.287-290. ⟨hal-01315717⟩