\(QS11_{11}^{(2)}\)

Description

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

Phase Portrait

Topological Invariants

TCSP	Fin Sep	Inf Sep
\(11\)	\(4430\)	\(3211\)

Example

The quadratic differential system

\[\begin{cases} \dot{x} = (cm \, x^{2})/10 - y + 2 \, ch \, x \, y \\ \dot{y} = x + (-2 \, ch + cl) \, x^{2} + (-cg + cm/10) \, x \, y + 2 \, ch \, y^{2} \end{cases}\]

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 \(BD41\) in {J. C. Artés}, Systems of class BD, {Preprint} (2026).
With name \(7S07\) in Missing reference in QWF1SN02