What does £ mean in mathematics?

Question

This is an excerpt from my textbook Data Structures and Algorithms:

" We say that T(n) is O(f(n)) if there are constants c and $n_o$ such that T(n) £ cf(n) whenever $n^3$ $n_0$."

While I get the meaning of the big O-Notation as the highest upper bound of the function, I don't quite understand what the £ means in this context. Can anyone tell me? A google search has not given me any helpful results unfortunately.

Answer 1

They meant to use $\leq$. Also, I believe the final part of the quote was meant to be "$n \geq n_0$".

We say that $T(n)$ is $O(f(n))$ if there are constants $c$ and $n_0$ such that $T(n) \leq cf(n)$ whenever $n \geq n_0$.