\(QS11_{21}^{(2)}\)

Description

Topological configuration of singularities: \(s,s,a,a;N,(0,2)SN\)

Phase Portrait

Topological Invariants

TCSP	Fin Sep	Inf Sep
\(11\)	\(4432\)	\(2120\)

Example

The quadratic differential system

\[\begin{cases} \dot{x} = -\frac{1}{10}00 + x^{2} + 6 \, x \, y + 3 \, y^{2} \\ \dot{y} = -\frac{1}{10}00 + x^{2} + y - 4 \, x \, y + 13 \, y^{2} \end{cases}\]

has the following phase portrait done with P4. If you want, you may download the P4 file here.

The phase portrait appears in the following papers

With name \(BD53\) in {J. C. Artés}, Systems of class BD, {Preprint} (2026).