# Thread: About accumulation points of a set in [0,1]

1. ## About accumulation points of a set in [0,1]

Hi!

If $\lambda>0$:
What are the accumulation points of $A=\left\{\lambda n-[\lambda n]:n\in\mathbb{N}\right\}$ in $[0,1]$?

2. ## Re: About accumulation points of a set in [0,1]

Is $[\lambda n]$ the floor function?

3. ## Re: About accumulation points of a set in [0,1]

Originally Posted by Gusbob
Is $[\lambda n]$ the floor function?
Yes.

4. ## Re: About accumulation points of a set in [0,1]

Originally Posted by Gusbob
Is $[\lambda n]$ the floor function?
It far more than that. Look at the webpage.

Originally Posted by eraldcoil
If $\lambda>0$:
What are the accumulation points of $A=\left\{\lambda n-[\lambda n]:n\in\mathbb{N}\right\}$ in $[0,1]$?
Well at least I have no worry that Soroban will give a complete solution to this one.

This is a great teaching question. DO IT!

First let $\lambda =\tfrac{1}{2}$ then $\lambda =\tfrac{1}{4}$ then $\lambda =\tfrac{3}{5}$.

Now what happens if $\lambda =\tfrac{\pi}{2}~?$

If you go back to that webpage, look at the graphs, what is going on?