This module is an extension to the Math::Symbolic module. A basic
familiarity with that module is required.

Math::Symbolic offers some builtin simplification routines. These,
however, are not capable of complex simplifications. This extension offers
facilities to override the default simplification routines through means
of subclassing this module. A subclass of this module is required to
define a simplify object method that implements a simplification of
Math::Symbolic trees.

There are two class methods to inherit: register and unregister. Calling
the register method on your subclass registers your class as providing the
simplify method that is invoked whenever simplify() is called on a
Math::Symbolic::Operator object.

Calling unregister on your subclass restores whichever simplification
routines where in place before.