Hello everyone, could anyone please tell me where can I find information about the Elton–Odell theorem?


It states:


For any infinite dimensional Banach space $X$ there is a $q > 1$ so that $X$ contains a sequence $(x\_n)$ with $\|x\_n\|=1$ and $\|x\_n-x\_m\|\ge q$, whenever $m\ne n$.


Thanks



Info about Elton–Odell theorem
J. Diestel, Sequences and series in Banach spaces, Springer-Verlag, New York, 1984.
(Chapter XIV, page 241)


