Talk:Half-Open Rectangles form Semiring of Sets

I'm not sure that this statement is even true. For example, how can $\left({0 \, . \, . \, 2}\right) \setminus \left({1 \, . \, . \, 2}\right) = \left({0 \, . \, . \, 1}\right]$ be written as a finite union of open intervals? I thought that it is the product of left-closed, right-open intervals that forms a semiring. Comments? –Abcxyz (talk | contribs) 09:26, 23 March 2012 (EDT)
 * Yes, that's entirely correct. I should have anticipated that there would be a reason for my source to work with left-closed, right-open ('half-open') intervals to start with, instead of trying to outsmart him. Thanks, page will be moved and amended as appropriate. --Lord_Farin 09:39, 23 March 2012 (EDT)