How is Big O notation useful when n_0 and C does not need to be unique?

224 views

The big O specifies 2 positive constants c and n_0 but there can be multiple c and n_0 values that are solutions. How can we decide which one is the best. What does having multiples solutions signify ?

In: 5

4 Answers

Anonymous 0 Comments

You don’t decide which one is best, none of them are best, and you don’t pay attention to them.
The definitions say “there exist a c, n_0, …” not because you’re supposed to find out what those c, n_0 are.
Even if you did bother to find them, the only reasonable thing to do with them would be to throw them in the garbage and forget about them immediately.

Think of it this way.
We can define a house to be “certified” if there exists an electrician who has examined it and said it’s safe.
You could say, but there could be multiple electricians!
You could have any number of electricians look at the house and say it’s safe!
How do we decide which electrician is the best?
What implications are there at having so many electricians certify the house??

And the answer is, none of it matters.
As soon as the house is certified, the house is certified.
Nobody cares who the electrician was.
If your goal is only to get a certification saying that the house is safe, there’s no point trying to define which electrician did the best job of saying “it’s safe”.

With Big-O, your only goal is to show that the function is bounded by another function.
The n_0 and c values are the electrician who says “yes, it’s bounded!”.
Okay, good, job done.
We don’t care about the specific values used.

You are viewing 1 out of 4 answers, click here to view all answers.