Hi,

As it is known that the "`young_project_tensor`

" command is to expand the tensor expression in some basis by using their young tableaux symmetry. This is powerful if one wants to compare different expressions or to show some identities such as the Bianchi identity for Riemman tensor.

But I often encounter the situation that I need to rewrite those expansions in basis back to the original tensors, or some more compact forms. I think I am kind of asking the question whether there is a reverse command to undo the "`young_project_tensor`

".

An example to explain my question is as following:

```
ex:= R_{a b c d} R_{a c e f} \gamma_{b d e f} + \frac{1}{2} R_{a b c d} R_{a b e f} \gamma_{c d e f};
young_project_tensor(_, modulo_monoterm=True)
distribute(_)
canonicalise(_)
rename_dummies(_);
```

it gives me

```
\frac{8}{9} R_{a b c d} R_{a c e f} \gamma_{b d e f} + \frac{4}{9} R_{a b c d} R_{a e c f} + \frac{4}{9} R_{a b c d} R_{a b e f} \gamma_{c d e f}
```

I know that this is nothing but

```
R_{a b c d} R_{a b e f} \gamma_{c d e f}
```

This is the easiest part in my computations, so I recognize it immediately.

But is there a way to directly convert the three-term expression to the compact one-term result?

Best,

Yi