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# Talk:Paracompact space

(Redirected from Talk:Paracompact)

I removed the following two statements:

• Of course, a fully normal space is normal.

That doesn't seem to be true, since fully normal spaces don't have to be Hausdorff.

Normal spaces don't have to be Hausdorff either.
Ok, Topology Glossary agrees, but normal space links to Separation axioms where "normal" appears in a table which suggests that normal spaces are T1 and hence Hausdorff, but then the glossary further down says that that's usually no longer true. This is a mess. AxelBoldt
The text following that table in Separation axioms and which explains that table describes how "normal" originally meant that a space satisfies both T4 and T1 but now only means that it satisfies T4. Of course, this is still a mess, but that is unavoidable; it's a mess in real life. The Topology Glossary, like the glossary in at the end of Separation axioms, explains what the term means in Wikipedia: the modern interpretation. The article Normal space itself should do so as well; right now it redirects only because nothing has been written on normal spaces as such. (There is much to write on that subject, however, and I'll be sure to do it someday.) Given the easy possibility for confusion, however, it'd be best to have an explanation right in Normal space itself, even if that makes it a pitiful stub; I'll do that now for anything that redirects to Separation axioms and is one of these controversial terms. — Toby Bartels, Wednesday, May 22, 2002 — Actually, on second that, I won't do that stuff, because you already did!!!
Steen & Seebach say that "fully T4" spaces are "T4"; since they use the older terminology for separation axioms, this means that fully normal spaces are normal. Since I trust Steen & Seebach's facts, if not their terminology, I'll restore this.
• Thus, a fully T4 space is the same thing as a paracompact Hausdorff space (see Separation axioms).

The term "fully T4" hasn't been defined. Or is this sentence supposed to be a definition?

The reference to Separation axioms is supposed to give the reader enough information to come up with a definition (that is, fully normal and T1). But this could be made clearer, which I will now do.
-- Toby Bartels, Monday, May 20, 2002

The definitions section can now be cut back, by referring to the open cover page. Charles Matthews 14:50, 13 Sep 2004 (UTC)

Last updated: 06-01-2005 02:55:32
03-10-2013 05:06:04