Just a question: If we had given intervals of s, like we said s = [1,3], then I totally understand what F-measurable means, it's like high = between 1 and 3, if o-algebra includes the set of all high sample points then it's F measurable - so for a given "division" s, we can look and see if it's F-measureable - But this gives us no specific s and just tells us it's F-measureable. idk