Talk:Classical Probability is Probability Measure

It occurs to me that the proof of the third axiom depends on the fact that the events are disjoint. So I browsed back to Classical Probability Model and couldn't find anywhere this was stated. I did find it in the statement of the definition of Probability Measure, though, but this time (as a naive reader) I've lost the track of where the assumption of disjointness comes.

In a proof like this where we are referring to a set of axioms, and in the proof we refer to another proof, all you've got is "it fulfis (x) axiom because of (y) result." I'm becoming unhappy with this approach (I've used it a lot in the past - in fact I think I still do) and I wonder whether it needs something more:

"Third axiom states that: blah blah. X result states that: yada yada. This-object fulfils the conditions for X result to hold, because yak blether. Therefore X result can be applied to this-object and so the third axiom is seen to hold."

I started doing that for some of the fiddly topological properties where a property holds merely by the interpretation of the definition of the property as applied to the object as defined. The proof in these cases is a one-liner, but the hard work is i explaining what the definition means in the context of the given page.

What does anyone else think? --prime mover 03:28, 11 December 2011 (CST)