**On transformations of the Rabelo equations**

**Abstract:**

We study four distinct second-order nonlinear equations of Rabelo which describe pseudospherical surfaces. By transforming these equations to
the constant-characteristic form we relate them to some well-studied integrable equations. Two of the Rabelo equations are found to be related to the
sine-Gordon equation. The other two are transformed into a linear equation and the Liouville equation, and in this way their general solutions are obtained.

This is joint work with Sergei Sakovich.