Sagemath module for working with (ramified) coverings of Riemann surfaces.

A (ramified) covering of Riemann surfaces is a holomorphic map $f\colon X \to Y$ between compact Riemann surfaces; hereinafter called just a covering. An automorphism of a covering is an isomorphism $g\colon X \to X$ such that $f = f\circ g$; the automorphism group of $f$ is the group of all automorphisms of $f$ operated by composition. A covering $f\colon X \to Y$ is Galois (or regular) if it is equivalent the the quotient of $X$ by the automorphism group of $f$.

The two main classes defined by this module are Covering and GaloisCovering; several methods are defined, which give information about the coverings, such as the genus, the total ramification or the intermediate coverings.