Confusing questions in section"vectors" 5.1.1

[skatz1995]

Hello,

Thanks for such great book!

I think that some questions in "vectors" section is confusing. For example, in the question 4
"Given two sets of vectors A and B. How do you check that they share the same basis?"

is it meant "how do you check that span of those sets of vector share basis"?

Also in the question 6, what is meaning of L_{norm}?