For example,

```
ex:=(a b)**{1/2};
expand_power(_);
```

Maybe some function like `Assumption`

in `Mathematica`

can be added.

0 votes

I found a way to do it. One can use function `refine`

in sympy, for example,

```
from sympy import refine, sqrt, Q
from sympy.abc import L
ex:=(\lambda**{-2})**{1/2};
substitute(_,$\lambda->L$);
refine(_._sympy_(), Q.positive(L));
```

But there is an another question: How to transform sympy expression to cadabra2 expression?