Chazy equation

In mathematics, the Chazy equation is the differential equation

$\frac{d^{3}y}{d{x}^3}=2y\frac{d^{2}y}{d{x}^2}-3{\left(\frac{dy}{dx}\right)}^2.$

It was introduced by Jean Chazy (1909, 1911) as an example of a third-order differential equation with a movable singularity that is a natural boundary for its solutions.

One solution is given by the Eisenstein series

$E_2(\tau )=1-24\sum {\sigma }_1(n)q^n=1-24q-72q^2-\cdots .$

Acting on this solution by the group SL₂ gives a 3-parameter family of solutions.

References

• Chazy, J. (1909), "Sur les équations différentielles dont l'intégrale générale est uniforme et admet des singularités essentielles mobiles", C. R. Acad. Sci. Paris (149) 
• Chazy, J. (1911), "Sur les équations différentielles du troisième ordre et d'ordre supérieur dont l'intégrale générale a ses points critiques fixes", Acta Mathematica 34: 317–385, doi:10.1007/BF02393131 
• "Symmetry and the Chazy equation", Journal of Differential Equations 124 (1): 225–246, 1996, doi:10.1006/jdeq.1996.0008, Bibcode: 1996JDE...124..225C