Nontrivial example of Finite intersection property

360 Views Asked by At

I know that Finite intersection property of compact set gives non-empty infinite intersection if any finite intersection is non-empty. I can prove this theorem. Using this theorem Nested interval property of compact set becomes corollary.
I am interested in the example of finite intersection property other than the nested interval. That I had not found .
P.S. I don't know topology till now So please give me the example which I can understand with analysis knowledge.
Any Help will be appreciated

1

There are 1 best solutions below

0
On

Fix a point on the real line, say 0. Then take any family of compact intervals all containing 0. You can easily get a family of intervals which are not nested.

But I am afraid this example is trivial in that sense that it is obvious by definition that any subfamily (not even finite) has a non-empty intersection.

A nicer example is the construction of the Cantor set. The family of the compact sets is nested but the members are not intervals - they are finite unions of intervals.