Hi everyone,

I have been recently working on metric spaces, doing some exercises about proving properties, integrability... But there's one I have not idea how to prove it (or maybe I should give an counterexample).

I have to prove if there exists a metric space (X,M,[tex]\mu[/tex]) such that {[tex]\mu[/tex](E) : such that E [tex]\in[/tex] M} = [0,+[tex]\infty[/tex]]\Q[tex]^{+}[/tex]

If anyone has an idea I would be delighted to read u, thanks in advan