TransformationFunctions is an option for Simplify and FullSimplify which gives the list of functions to apply to try to transform parts of an expression.
The default setting TransformationFunctions->Automatic uses a built-in collection of transformation functions.
TransformationFunctions->, , ... uses only the functions .
TransformationFunctions->Automatic, , , ... uses built-in transformation functions together with the functions .
See Section 3.3.9.
See also: Simplify, FullSimplify, ReplaceAll, ExcludedForms, FunctionExpand.
New in Version 4.