# Topology question

• May 4th 2012, 04:30 AM
hairymclairy
Topology question
How do I show that convergence is a topological property?

Thanks.
• May 4th 2012, 05:23 AM
Plato
Re: Topology question
Quote:

Originally Posted by hairymclairy
How do I show that convergence is a topological property?

What are the exact properties of a homeomorphism?
Now think:"How are continuity and convergence related?"
• May 4th 2012, 05:26 AM
Sylvia104
Re: Topology question
Let $\displaystyle f:X\to Y$ be a homeomorphism between topological spaces $\displaystyle X$ and $\displaystyle Y.$ If $\displaystyle \left(x_n\right)_{n=1}^\infty$ is a sequence in $\displaystyle X$ converging to $\displaystyle x\in X,$ show that the sequence $\displaystyle \left(f(x_n)\right)_{n=1}^\infty$ in $\displaystyle Y$ converges to $\displaystyle f(x)\in Y.$

The sequence $\displaystyle \left(x_n\right)_{n=1}^\infty$ converges to $\displaystyle x\in X$ iff for every open set $\displaystyle U\subseteq X$ containing $\displaystyle x$ there exists a natural number $\displaystyle N$ such that $\displaystyle x_n\in U$ for all $\displaystyle n>N.$