I’m having trouble even checking for syntactic equivalence

```
julia> using Symbolics
julia> @variables t
1-element Vector{Num}:
t
julia> (t^2 - t^3) == (t^2 - t^3)
(t^2 - (t^3)) == (t^2 - (t^3))
julia> (t^2 - t^3) === (t^2 - t^3)
false
```

I’d like a comparison that recognizes that

```
-t^3 + t^2 == t^2 - t^3
```

That is, algebraic equivalence, not just syntactic equivalence.