https://en.wikipedia.org/wiki/Big_O_notation
($O$ or $mathcal{O}$)
- $f(x)=O(g(x))$
f(x) is asymtotically bounded above by g(x) up to a constant factor
- $f(x)=Theta(g(x))$
f(x) is asymtotically bounded above and below by g(x) up to constant factors
- $f(x)=Omega(g(x))$
f(x) is asymtotically bounded below by g(x) up to constant factors
- $f(x)=o(g(x))$
f(x) is asymtotically dominated by g(x)
- $f(x)=omega(g(x))$
f(x) asymtotically dominates g(x)