# Does a subtraction symbolic expression actually exist?

Can someone please give me an example of a symbolic expression in sage of the subtraction variety? (by subtraction variety I mean using the subtraction operator)

Precisely: how can I create an object `o`

of type `sage.symbolic.expression.Expression`

such that `o.operator()`

is `operator.sub`

? It seems that subtraction expressions are always converted to additions.

For example:

```
sage: x = var('x')
sage: (x-1).operator()
<built-in function add>
```

Apparently we don't use this, though ginac does seem to have a `sub` subtraction thing. Interesting.

subtraction is not a nice operator; it's not associative!