Hi !

This is a proof my teacher wanted us to do, but when coming to giving the solution, he got confused

The problem is :

Where is 'the negative part of the function' :

etc...

Also, is a sequence of measurable functions, but I'm not sure it intervenes here.

As a sidenote, this was used in a proof of the generalization of Beppo-Levi's lemma.

Thanks in advance !