- #1
Fractal20
- 74
- 1
Homework Statement
Hi all, I am struggling with getting an intuitive understanding of linear normed spaces, particularly of the infinite variety. In turn, I then am having trouble with compactness. To try and get specific I have two questions.
Question 1
In a linear normed vector space, is it true that limit point compactness, compactness, and sequential compactness are all equivalent? My understanding is the norm creates a metric space and these should all be true. But I had an earlier confusion that perhaps compact spaces of the infinite variety need not be bounded. So I'm unsure about this point.
Question 2
In this same direction, would a compact subset of an infinite banach space have to have a finite span? We proved in class that B* space is finite dimensional iff the unit sphere is compact so this is what makes me assume this would be true. It seems like if not, then we could create an infinite sequence of orthogonal vectors and it doesn't seem like this sequence would not have to have a convergent subsequence.