Refine[expr, assum] gives the form of expr that would be obtained if symbols in it were replaced by explicit numerical expressions satisfying the assumptions assum.
Refine[expr] uses default assumptions specified by any enclosing Assuming constructs.
Example: Refine[Sqrt[x^2], x > 0] .
Assumptions can consist of equations, inequalities, domain specifications such as x Integers, and logical combinations of these.
Example: Refine[Sqrt[x^2], x Reals] .
Refine can be used on equations, inequalities and domain specifications.
Quantities that appear algebraically in inequalities are always assumed to be real.
Refine is one of the transformations tried by Simplify.
Refine has the option Assumptions, with default setting $Assumptions.
Refine[expr, a, Assumptions->b] uses assumptions a && b.
See Section 3.3.10.
See also: Simplify, PowerExpand, Assuming.
New in Version 5.0.