  We assume some standard choices for the branch cuts of a group of functions
and consider the problem of then calculating the branch cuts of expressions
involving those functions. Typical examples include the addition formulae for
inverse trigonometric functions. Understanding these cuts is essential for
working with the single-valued counterparts, the common approach to encoding
multi-valued functions in computer algebra systems. While the defining choices
are usually simple (typically portions of either the real or imaginary axes)
the cuts induced by the expression may be surprisingly complicated. We have
made explicit and implemented techniques for calculating the cuts in the
computer algebra programme Maple. We discuss the issues raised, classifying the
different cuts produced. The techniques have been gathered in the BranchCuts
package, along with tools for visualising the cuts. The package is included in
Maple 17 as part of the FunctionAdvisor tool.

Mathematical Software;Symbolic Computation