[danharaj]

Sure it is, O notation denotes equivalence classes and being part of the same equivalence class is a perfectly cromulent notion of equality.

[gizmo686]

Big-theta gives you equivalence classes. Big-O only gives you partial ordering.

For instance, we might say x = O(x^2) and x=O(x), but we would not say O(x^2)=O(x).

Interestingly, in my experience, some people will actually say O(x)=O(x^2), but that seems a bit too abusive for my liking.

[danharaj]

Yea, my mistake :)