kathrynag
- 595
- 0
Homework Statement
If E_{1},...E_{n} are compact, prove that E=\cup^{n}_{i=1}E_{i} is compact.
Homework Equations
The Attempt at a Solution
A set E is compact iff for every family {G_{\alpha}}_{\alpha\in}A of open sets such that E\subsetU_{\alpha\in}A G_{\alpha}
Let G_{\alpha}=E_{n}.
Let E=(i,n)
If i<x<n, there is a positive integer n such that E_{n}<x, hence x\inG_{n} and E\subsetG_{n}.
Not quite sure about this one.