### Computing the inverse of a function with parameter(s)

I have adapted the code shown in the answer of "Can Sagemath compute the inverse of a function?". In the original exemple, the function was $log(x)$ so there is no parameters. But I would like to do the same with $x^a$. But even if i insert an `assume`

command, I finally fall on an error. Here is my code

```
var('x,y,a')
assume(0<=a<=1)
U(x) = x^a
V(x) = solve(x == U(y), y)[0].rhs()
show(V)
```

Is there a way to obtain the result $x^{1/a}$ ?