User talk:Point-set topologist

Your Spanish translation at the language ref desk

How did you come up with this translation? Joeldl (talk) 13:04, 18 January 2009 (UTC)

Welcome

Welcome, PST! I am surprised to see that no one has properly welcomed you here. I have transcluded below a standard {{welcome}} message. If you have any questions at all or problems here, please do not hesitate to drop by my talk page. Alternatively, I have found that User:Jitse Niesen is generally quite willing to help new users. If you need typesetting advice, User:Michael Hardy is the uncontested guru. Most importantly, please enjoy your time here. siℓℓy rabbit (talk) 01:13, 19 January 2009 (UTC)

Here is the template, as promised:

Welcome!

Hello, Point-set topologist, and welcome to Wikipedia! Thank you for your contributions. I hope you like the place and decide to stay. Here are some pages that you might find helpful:

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Thankyou! I appreciate your help. --PST 10:02, 19 January 2009 (UTC)

Hi

Hey, I noticed you were wanting a good article review of Ring (mathematics). Could I suggest you follow the instructions at Wikipedia:Good article nominations? If I get time I will gladly review it.

By the way, how's life? My email address is still working if you ever want to use it ;) Martin^Msgj 23:33, 19 February 2009 (UTC)

Replied

I replied to you. Take your time. Best regards, siℓℓy rabbit (talk) 01:55, 4 March 2009 (UTC)

Cavalieri and Borsuk-Ulam

Could you add a little detail to this edit explaining (in the see-also section) why this link is relevant? Nothing in the Cavalieri article explicitly mentions Borsuk-Ulam, nor vice versa, so as it is the link is completely bewildering. —David Eppstein (talk) 04:31, 6 March 2009 (UTC)

How about this? --PST 11:02, 6 March 2009 (UTC)

Might save you some trouble

A while ago I commented there is some organization for people who want to mentor new Wikipedians. I found it: Wikipedia:Adopt-a-User. I think it's worth for you to take a look. --C S (talk) 07:20, 7 March 2009 (UTC)

Thanks! I will most certainly have a look at it. --PST 10:25, 8 March 2009 (UTC)

Derivation disambiguation

In this edit, you linked to derivation. I clicked on it and as I expected, it's a disambiguation page. Doesn't common sense lead you to expect that? I changed your link so that it says derivation (abstract algebra). Michael Hardy (talk) 17:19, 18 March 2009 (UTC)

I guess I forgot that there were things apart from mathematics. --PST 01:15, 19 March 2009 (UTC)

Constructive comments at WP:RD/MA

PST, The reference desk is intended to help posters understand their mathematical questions better. Unfortunately, by criticizing the quality of comments from other ref-deskers, you have not been helping the purpose of the ref-desk. Your comments may discourage other users from participating. If you feel that another user's actions are actively malacious or harmful, then it would be most appropriate to address them on their talk page. Please consider your comments more carefully regarding whether they are constructive before posting.

Further, although you may have felt that that particular comment is not helpful, please keep in mind that many mathematical questions can be answered in a wide variety of ways, and that different approaches may be most helpful to different people. Although you felt a particular response was not helpful, the OP may have found that response useful to his or her understanding.

Thanks. Eric. 131.215.159.99 (talk) 08:30, 13 April 2009 (UTC)

ó

In my user name the 'ó' has no relation to Spanish language. It's just a joke. We have a letter for phoneme /oː/ (a bit like the end of 'Frodo', it can be written this way as 'Frodó'). Is it right that, mozo (or kind of) means porter in Spanish? Regards, Mozó (talk) 14:01, 20 April 2009 (UTC)

Thankyou for the reply. I am interested in many of the European languages but unfortunately do not know many. In particular, I do not know of the Hungarian alphabet. Actually, many Spanish idioms are formed using mozo. For example, "buen mozo" may mean "handsome" whereas "mozo de cordel" may mean "porter (male)". Most of the time however, the context in which it is used is "buen mozo" or "handsome". --PST 14:36, 20 April 2009 (UTC)

Group

I'm standardizing the definitions and formats for group, semigroup, magma, monoid, etc. Stop undoing them. They're not finished. —Preceding unsigned comment added by 67.194.143.86 (talk) 01:27, 25 April 2009 (UTC)

Please assume good faith on my part. It is not my intention to destroy your work; rather I wish to note that your edits do not conform to that required by FA standards. --PST 01:48, 25 April 2009 (UTC)

I understand it was not malicious, but I disagree with you on this topic. The definition should be in its own section at the beginning so that those who wish to find it do not have to read through motivation after motivation. Negi(afk) (talk) 02:07, 25 April 2009 (UTC)

IP

What does IP stand for? You keep calling me that, and I was just wondering what it meant. —Preceding unsigned comment added by Negi(afk) (talk • contribs) 03:37, 25 April 2009 (UTC)

It stands for "Internet protocol" but commonly referred to as "IP adress" rather than "IP". --PST 04:05, 25 April 2009 (UTC)

Countable, T₂, and connected

I enjoyed telling your irrational-slope counter-example to various people. It is nice that one can explain it just walking or having luch. And at the first glance, it looks like a fool invention, but at the end it suddenly reveals the genial purpose. Thanks! --pma (talk) 10:44, 17 June 2009 (UTC)

Sorry for the rudeness

You are right. My edit summary was rude and uncalled-for. I sincerely apologize. Sławomir Biały (talk) 00:07, 10 July 2009 (UTC)

That is fine. I too dislike seeing versions of theorems which are uncommon but given higher priority than more common versions (for instance, I have seen weak corollaries of some theorems replace the theorem itself). Having another look at Nakayama's lemma, I think that the article is much better after your improvements (and the sourcing of other texts), and certainly far better than what I could ever have done. --PST 00:53, 10 July 2009 (UTC)

Rubbish

If using the word "rubbish" in an edit summary is rude and unnecessary, then this is a clear case of the pot calling the kettle black: [1], [2], [3], [4], [5]. Furthermore, an equally descriptive yet more "polite" alternative such as the one you suggested would certainly not have fit in the edit summary field. Sławomir Biały (talk) 13:16, 24 August 2009 (UTC)

I have replied on your talk page, but do not deny that those edit summaries are correct. --PST 04:02, 25 August 2009 (UTC)

Hallo

By the way, have a look to this [6] sometimes, should it have some activity -workshops/schools/meetings of interest for you. In that case, we can share a break-lunch, and even the lunch! Cheers, --pma (talk) 17:51, 30 October 2009 (UTC)

Hello, Point-set topologist. You have new messages at JamesBWatson's talk page.
You can remove this notice at any time by removing the {{Talkback}} or {{Tb}} template.

Regarding the revert

Regarding your edit summary here:

"I never imagined that so many people are too tied to the "geometric notion" of the derivative that they cannot imagine a definition of the concept in more abstract contexts"

This speculation on what I can and cannot imagine is totally uncalled for. Please focus your comments on the content, not on the editors. Incidentally, I am aware that the derivative of any function with values in a zero-dimensional manifold is zero, but is certainly not something that one is used to considering because it is, by definition, a trivial degenerate case of a much more interesting general concept. The text you have added to the article is muddled and inappropriate to the intended level. I recommend that either my version, or some other version, should be restored. 173.75.158.194 (talk) 11:29, 5 November 2009 (UTC)

I'm afraid I had to revert your edit as unsupported by sources. Also, I am unfamiliar with any definition of the derivative that applies for mappings between topological spaces lacking a differentiable structure. Perhaps you could, for my own personal edification, supply a reference. 74.98.44.216 (talk) 03:16, 8 November 2009 (UTC)

(It doesn't matter anymore, as Charles Matthew's has removed the section for the reason that it is "based on too many misconceptions", a reason that I think I can agree with after various discussions pertaining to the example.)

Thank you for the reply. I agree that locally ringed spaces have well-defined tangent spaces, but the local ring structure is something in addition to the topology (e.g., the sphere and circle are homeomorphic in the Zariski topology; exotic spheres are homeomorphic but not diffeomorphic, etc.) But there is something like the tangent microbundle (which is a redlink as of writing this) that (correct me if I am wrong) is defined for arbitrary topological spaces? 71.182.244.158 (talk) 13:31, 8 November 2009 (UTC)

Hello

Yes, I am back for the time being. Thanks, Sławomir Biały (talk) 14:21, 15 November 2009 (UTC)

Whoa. Looks like even the reference desk isn't safe from Wikidrama.  ;-) Sławomir Biały (talk) 13:23, 16 November 2009 (UTC)

Unfortunately, no. However, fighting off IP's is a much easier task compared to fighting off established users. I'll let the IP's make the Wikidrama for the time being. ;) --PST 02:44, 17 November 2009 (UTC)

I've replied

Hi PST, I've replied to your comment at Talk:mathematician. Paul August ☎ 18:16, 16 November 2009 (UTC)

RD/Math - sock puppet allegations

Hello PST, I'm reviewing your recent interactions at the Maths Reference desk and your accusation of sockpuppetry against Dr Dec. You should know that making such an accusation is a serious charge and you need to have very solid ground if you are to proceed. I would suggest that you should instead examine your own comport at RD/Math to be sure it fits with community norms. On the RD's I participate at, we go by the standard that if you don't think a question is good enough you either 1) ask for clarification; or 2) ignore it. Other people seemed quite able to answer the one-word "tesselation" question, so there was no need for you to threaten the OP with words like "vandalism".

Additionally, I would suggest that if you wish to discuss subjects other than the OP question itself (such as whether the OP is acting in good faith), you should conduct those discussions at the RD talk page rather than directly in the thread. The public face of the RD's should be only about answering questions, we can do all the "internal" stuff on the talk page. Regards! Franamax (talk) 13:32, 17 November 2009 (UTC)

Hi PST, I just wanted to say that (1) I can understand your initial reaction very well, (2) it's generally a good idea not to make sockpuppetry accusations without very good evidence and not to make them in relatively marginal situations such as this one, and (3) ignoring the trolls is usually the best strategy, even when they get creative to get attention. (I am not saying that this happened here, merely that it's a useful interpretation.) By the way, I often suspect sockpuppetry and am quiet about it most of the time. So far all my sockpuppetry complaints ended in confirmation, but in the majority of cases I found conclusive evidence that I was wrong before I made the suspicion public. I am available if you need a second opinion at some time in the future. Hans Adler 13:41, 17 November 2009 (UTC)

PST, thanks much for your graceful followup on this, you've done the right thing. 'Tis all behind us now, on to the next questions! :) (And it sure won't be me answering the maths questions, selecting the right weld rod - that I can help with, and I welded all my math textbooks shut years ago :) Franamax (talk) 01:37, 19 November 2009 (UTC)

Box product

Hi,

Box product, which redirects to Box topology can be easily confused with Triple product, although, a disambig page for Box product may be more appropriate.

SPat ^talk 14:01, 19 November 2009 (UTC)

Hello

Thanks for the welcome! I feel Korean whenever I type my signature... Expz (talk) 22:24, 22 November 2009 (UTC)

No apology needed. Everyone does it. For example, I once proclaimed to my students in an algebra class that R was not an ideal of R. Expz (talk) 10:03, 13 December 2009 (UTC)

Still Reading

Thanks for responding...I am still reading your response...will post here if I have further question...Thanks. --33rogers (talk) 08:38, 27 November 2009 (UTC)

$b^{\log _{b}(x)}=x$

I got this:

Suppose $log_{b}(x)=y\,$; then by definition, $b^{y}=x\,$

(The above being exponent to b)

but I keep getting stuck on where you are substituting what?

--33rogers (talk) 08:41, 27 November 2009 (UTC)

maybe you have logged off...I will post in Reference desk the follow up....thanks.--33rogers (talk) 08:46, 27 November 2009 (UTC)

Thank you for your last response to my question. I finally understood when you put it line by line.

1. $y=\log _{b}(x)$

2. $b^{y}=x$

3. $b^{\log _{b}(x)}=x$

Thanks. --33rogers (talk) 21:43, 29 November 2009 (UTC)

I have marked you as a reviewer

I have added the "reviewers" property to your user account. This property is related to the Pending changes system that is currently being tried. This system loosens page protection by allowing anonymous users to make "pending" changes which don't become "live" until they're "reviewed". However, logged-in users always see the very latest version of each page with no delay. A good explanation of the system is given in this image. The system is only being used for pages that would otherwise be protected from editing.

If there are "pending" (unreviewed) edits for a page, they will be apparent in a page's history screen; you do not have to go looking for them. There is, however, a list of all articles with changes awaiting review at Special:OldReviewedPages. Because there are so few pages in the trial so far, the latter list is almost always empty. The list of all pages in the pending review system is at Special:StablePages.

To use the system, you can simply edit the page as you normally would, but you should also mark the latest revision as "reviewed" if you have looked at it to ensure it isn't problematic. Edits should generally be accepted if you wouldn't undo them in normal editing: they don't have obvious vandalism, personal attacks, etc. If an edit is problematic, you can fix it by editing or undoing it, just like normal. You are permitted to mark your own changes as reviewed.

The "reviewers" property does not obligate you to do any additional work, and if you like you can simply ignore it. The expectation is that many users will have this property, so that they can review pending revisions in the course of normal editing. However, if you explicitly want to decline the "reviewer" property, you may ask any administrator to remove it for you at any time. — Carl (CBM · talk) 12:33, 18 June 2010 (UTC) — Carl (CBM · talk) 13:33, 18 June 2010 (UTC)

Thanks for letting me know! PST 03:06, 20 June 2010 (UTC)

My pseudo-topology question

PST, thanks a lot for your replies to my question. I didn't really keep up to date with that thread, and I missed your replies. I've just seen them now. They were most informative, and I wanted to give you my thanks. So here you are: Thanks! — Fly by Night (talk) 22:50, 9 August 2010 (UTC)

Topology Axioms

I remember reading somewhere that the axiom that the whole set X and the empty set ∅ be open is redundant. That it is somehow implied by the other two axioms, i.e.

• The union of open sets is an open set.
• The finite intersection of open sets is an open set.

Have you heard of this before? I've tried to find where I read it, but I can't seem to. — Fly by Night (talk) 23:01, 9 August 2010 (UTC)

Did you hear this with relation to an Euclidean topology or some other naturally occuring topology? It cannot be redundant in general since if we take a non-empty set X and choose a non-empty proper subset U of X, then the "topology" on X consisting only of U would satisfy the two axioms you stated but would not contain X nor the empty set. Of course, this is a trivial example.

Suppose we call a collection of subsets of a set X a "relevant topology" (this is not a real name; just something I made up just now so it is easier to talk about these things) if it satisfies every axiom except possibly that "X and the empty set are in the topology". Then a non-empty set with a "relevant topology" that is Hausdorff (here "Hausdorff" means that any two distinct points are separated by neighborhoods; the same definition as the usual one on topological spaces) would necessarily have to include the empty set in the "topology". Thus for "many" topological spaces, requiring the empty set to be open is indeed redundant.

On the other hand, the requirement that the whole set X be open is in general not redundant with fairly natural topologies (I suppose). For example, take any topological space X and let Y be a set containing X as a proper subset. Declare a subset of Y to be open if and only if it is in the topology on X. Then this "relevant topology" on Y satisfies every axiom that a topological space should satisfy except that Y itself is not open. For example, X could be some Euclidean space with the standard topology (and Y could be any set containing X as a proper subset). But this construction is probably not very interesting since (at least as far as I can see) there is not any new information or insight obtained.

This might be too elementary for you, but I wrote the following section in open set a while back that roughly describes why the axioms are the way they are and the motivation for the abstract formulation of a topology: Open_set#Motivation. The following discussion at MathOverflow may perhaps be more appropriate to your question: Do the empty set and the entire set really need to be open?. PST 07:53, 10 August 2010 (UTC)

I hope Point-set Topologist won't mind if I join in. Technically the empty union, that is the union of all the sets in an empty family of sets, contains all elements in any set in the family, but there are no sets in the family, so it equals the empty set. And the empty intersection, the intersection of all the sets in an empty family of sets, is the universal set, because an intersection of the sets is the complement of the union of the complements. Since the family of sets is empty, so is the family of complements. The union over that empty family is therefore empty, and its complement is the universal set. It makes more sense using symbolic logic than it does using words.

One reason we need the empty set and the universal set to be open because we want the constant map to be continuous. Consider the map f(x) = p, where p is any point in the codomain of f. The inverse image of any open set containing p is the universal set (the domain of f) while the inverse image of any open set not containing p is the empty set.

Rick Norwood (talk) 12:22, 27 August 2010 (UTC)

Hi there

Wanna email me and 'splain what you're doing while you're logged out? - Alison ^❤ 07:59, 26 August 2010 (UTC)

Rings

Thanks for your comments on my edit to ring (mathematics), though I wish you had modified what I wrote instead of reverting it. Of course, I should not be surprised that we disagree, since I'm an algebraic topologist and you're a point-set topologist -- worlds apart. : )

I hope you will help find a more acceptable first paragraph that is intelligable to the lay reader.

Rick Norwood (talk) 12:11, 27 August 2010 (UTC)

Rick, I greatly appreciate your edits and do not want to give you the impression that they were not considered - I really do mean this. I have reinstalled your edits to the article. I am more than happy to discuss any changes to your introduction that are necessary on the talk page of the article. I think that your introduction was very good and with minor fixing, could really work out. My initial concerns were more to do with the fact that the article started off somewhat awkardly, but I believe this can be fixed. I hope you do not mind. Best, PST 13:33, 27 August 2010 (UTC)

(Note that while my username is indeed "Point-set topologist", that is not my primary research interest! (I know it is confusing ...) Actually, the reason I choose my name was more to do with the fact that most of my research interests, e.g., algebraic topology, algebraic geometry, C* algebras, and algebra in general (especially finite group theory and representation theory) have the general theme of "point-set topology". (Especially the first three.) They are not quite the same as "point-set topology" of course, but choosing a username such as C* algebraist might have been somewhat awkward seeing as there is already an user called Algebraist! "Point-set topologist" just has that nice "feeling" to it. (Perhaps that is because I am now used to it ...)) PST 13:40, 27 August 2010 (UTC)

Just out of curiosity, are you the Rick Norwood? PST 13:46, 27 August 2010 (UTC)

Nobody has ever asked me that question before, but I'm the only Rick Norwood I know. What prompted the question? Rick Norwood (talk) 15:50, 27 August 2010 (UTC)

I was just wondering ... Since I thought "Rick Norwood" was a fairly common name, it was not obvious that you were the same person as Rick Norwood. Just a question I guess ... PST 23:38, 27 August 2010 (UTC)