\(QS7_{1}^{(2)}\)

Description

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

Phase Portrait

Topological Invariants

TCSP	Fin Sep	Inf Sep
\(7\)	\(4210\)	\(4111\)

Example

The quadratic differential system

\[\begin{cases} \dot{x} = ce + x^{2} + 2 \, ch \, x \, y - 2 \, (1 + ch) \, y^{2} \\ \dot{y} = -x^{2}/2 + y + 2 \, (2 + ch) \, x \, y + (-9/2 - 2 \, ch) \, y^{2} \end{cases}\]

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 \(BD17\) in {J. C. Artés}, Systems of class BD, {Preprint} (2026).