I cannot find any solution to this following problem.
Let $\displaystyle f,g$ integrable functions over a measure space. if $\displaystyle \mu (\{x\in X: f(x) \geq t\} \triangle \{x\in X: g(x) \geq t\}) = 0, \forall t\geq 0$, then $\displaystyle f=g a.e.$
Thanks,
everk