问题
I've been trying for the better part of an hour to find reference to the following:
f = Ω(g)
But I have had no luck at all. I need to answer a question for an assignment and I can't find references.
The assignment is basically asking me to indicate what it (f = Ω(g)) means, in the context of the following choices:
- f = Ω(g(n))
- g = o(ln n)
- g = o(g(n))
- g = O(f)
- f = O(g)
Initially, I thought that perhaps there is an error in the question.
I know option 1 is wrong and assume option 5 is also wrong, but after an hour online I couldn't figure out which one is the answer.
Can someone please explain to me how to figure this out? I realize that might mean giving me the answer so it can be explained, but I'm more interested in why one of these answers are correct.
回答1:
"f = Ω(g) means "f is bounded below by g asymptotically". f = O(g) means "f is bounded above by g asymptotically" as per the comments.
If a river's upper bound is a bridge, what's a bridge's lower bound? The river.
I would suggest d
(For completeness, the "little" versions of these imply a very strong difference in growth.)
来源：https://stackoverflow.com/questions/16716291/big-omega-notation-what-is-f-%ce%a9g