Hi All;
I need The solution of the following question"
Let X be a set of measurable functions from a measurable set I to \Re , then we defined a metric d on X By
d(f,g)=\inf_{\varepsilon\longrightarrow0}(\varepsi  lon+m(t:|f(t)-g(t)|\geq \varepsilon)),
Then prove that d is a metric on X.