Talk:Union (set theory)

Move issues

Resolved

Because this page was moved without using the "Move this page" feature and the edit history was later recombined, this history may look odd near 2002 April 6 and 2003 February 7. However, every version saved is in the history at its correct date. -- Toby 00:27 Mar 5, 2003 (UTC)

Definite problem

Resolved

There is a very clear problem with the picture on this page and/or the picture on the intersection page. If you pay attention they are the same picture. Being as they are opposites, I find it unlikely that the middle section of a Venn Diagram of A and B is both AuB and AnB LFStokols 03:46, 9 March 2007 (UTC) LFStokols

So far as it seems, this issue has been resolved. J O R D A N ^[talk ] 20:45, 13 June 2008 (UTC)

Infinitary intersection

The article mentions the infinitary intersection; but I think there must be a warning that the "infinitary intersection" of no sets is not defined (unless we accept that it is the class of all sets): $\bigcap_{x \in \varnothing} x = ?\,$. Contrast this with the infinitary union, that is defined for all sets. Albmont (talk) 13:19, 15 December 2008 (UTC)

Confusing...

With all the mathematical symbols and language all over the place from the get-go, this article is impossible to follow. Isn't a union just everything that is in all the sets? What more is there to say? --Jubilee♫clipman 08:01, 9 February 2010 (UTC)

When a concept from set theory is being discussed I think you should expect mathematical symbols to be used, after all you wouldn't expect a discussion of addition (in the arithmetical sense) to forgo use of the symbol "+" would you? 213.122.23.20 (talk) 23:16, 21 February 2010 (UTC)

"Infinite" unions

The title of section 2.2 "Infinite unions" is misleading, M may be finite. 213.122.23.20 (talk) 23:05, 21 February 2010 (UTC)