### 2.12.15 Normal form for rational fractions : `ratnormal`

`ratnormal` rewrites an expression using
it’s irreductible representation. The expression is viewed
as a multivariate rational fraction with
coefficients in ℚ (or ℚ[*i*]). The variables are
generalized identifiers which are assumed to be algebraically independant.
Unlike with `normal`, an algebraic extension
is considered as a generalized identifier. Therefore `ratnormal`
is faster but might miss some simplifications if
the expression contains radicals or algebraically dependant transcendental
functions.

Input :

`ratnormal((x``^`

`3-1)/(x``^`

`2-1))`

Output :

`(x``^`

`2+x+1)/(x+1)`

Input :

`ratnormal((-2x``^`

`3+3x``^`

`2+5x-6)/(x``^`

`2-2x+1))`

Output :

`(-2*x``^`

`2+x+6)/(x-1)`