# Talk:Borel-Cantelli lemma

The edit changed one formula without correcting the rest of the article accordingly. Before, a set $A$ was defined and used. After, $A$ is still defined, but replaced with $\limsup A_n$ once, and then used again. This is not serious. I revert. Boris Tsirelson (talk) 21:16, 6 October 2014 (CEST)
Tastes differ. I use $\mathbb{P}$ when P(A) could be replaced with words "probability of A" (as is the case in this article). But if a probability measure P is explicitly mentioned (the more so, several probability measures, say P and Q) then I prefer $\mathrm{P}$ or $\boldsymbol{P}$ or just $P$. Boris Tsirelson (talk) 13:12, 8 October 2014 (CEST)