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.

WWW: http://search.cpan.org/dist/Math-Symbolic-Custom-Simplification