I am working on an algorithm which approximates a certain optimal quantity. The approximation becomes better when the size of the problem ($n$) becomes larger: the difference from the optimum is approximately $1/n$.
Initially, I wrote that the algorithm achieves an approximation of:
But, now I am not sure this notation is correct: it is just like writing $\Omega(1)$ (the smaller element is swallowed in the larger element, which is 1).
Should I write:
Which of these is the correct notation?