User talk:JackSchmidt/Archives/2008/07

Relevant question deleted from help-talk page

Why was my question removed from Help:Show_preview?

I suppose any question can be cast as a "help request". How was it "misplaced"?

The question was asked on the talk page for an article which is supposed to describe how to preview an edit.

The preview doesn't show references when editing a section.

I suppose the issue could have been raised in a number of places. I don't see that erasing the question is going to help in getting the feature added - or address the same question which others are likely to ask.

Thanks for noting a work-around in the edit history.

I don't usually look at the edit histories when looking for information which I expect to be in the body of an article.- Ac44ck (talk) 02:07, 3 July 2008 (UTC)

replied on their talk page. JackSchmidt (talk) 16:52, 3 July 2008 (UTC)

Perfect space and Countably compact space

Dear Jack,

If you are not too busy, could you please have a look at the following articles?

• Countably compact space
• Perfect space

I think that I am starting to understand how to write a proper article but it would always help to have some pointers. Thanks for all your help.

Topology Expert (talk) 10:37, 3 July 2008 (UTC)

replied on their talk page, made these minor changes. JackSchmidt (talk) 16:55, 3 July 2008 (UTC)

Concern

Thanks for that prompt response, I appreciate it. Richard Pinch (talk) 07:08, 4 July 2008 (UTC)

second thoughts about the right emphasis

Hi Jack,

I've thought more about your comment on my talk page regarding WP:V and WP:RS and now see better the wisdom in this emphasis. Thanks for the pointer. Oded (talk) 17:47, 5 July 2008 (UTC)

Order topology

Dear Jack,

Regarding what discrete topologies can be induced from order topologies, I am pretty sure that only the topologies on countable discrete spaces can be induced from order topologies (which is what you said). Intuitively this is because in countable spaces, you can always 'speak' of the next largest element in the set whereas you cannot speak of the next largest element of an uncountable discrete space. So basically, the property of uncountable ordered sets is that if x is in S (S being the uncountable ordered set), y is in S and x < y, then there exists z in S such that x < z < y (note that this isn't true for all uncountable ordered sets as S = (-infinity, 0) U {1,2} shows) I think you could prove your claim using this property (which holds for most subsets of an uncountable ordered set) of uncountable ordered sets. Perhaps using Hausdorff's maximum principle may be of some use (given an uncountable ordered set X and a subset Y of X that has this property, you could find a subset of X that contains Y and is maximal with respect to this property).

Also, I think that if X is an ordered set carrying the order topology and Y is a subspace of X, then the subspace topology on Y can be induced from the order topology on Y if Y is convex. I can think of topological proofs of such a fact but an algebraic proof is somewhat harder. I will probably have to try this.

Topology Expert (talk) 02:14, 7 July 2008 (UTC)

TfD and NPA

I was curious if it was appropriate to warn experienced users about WP:NPA? On a recent TfD discussion, it seemed like OwenX violated this in a clear fashion, and Ned Scott in a lesser fashion. However, it wasn't clear if you three were just old friends (I find it hard to believe strangers would communicate in this way). Would it be better to mention such things to uninvolved administrators?

In case you guys are old friends, you might want to make this clearer in the discussion, since it does create a bit of a chilling effect on the discussion. JackSchmidt (talk) 19:40, 7 July 2008 (UTC)

Jack, if you want to issue me a NPA warning, feel free to do so. Perhaps I shouldn't have lowered myself to the level of the other two editors. I find it amazing when experienced editors are eager to delete rather than try and understand. Even more contemptible is the habit of jumping in and interjecting a "pwned!!" whenever someone tries to opt out of a pointless argument.

More to the point, there are exactly four reasons for deleting a template. Finding "odd" language in a template isn't one of those reasons, especially when such a shortcoming can be easily fixed by editing the template. Trying to get rid of a template instead of spending a few seconds to fix it smacks of bad faith, don't you think? Owen× ☎ 20:43, 7 July 2008 (UTC)

replied to this, in regards to my message to MBisanz about a tfd. JackSchmidt (talk) 21:21, 7 July 2008 (UTC)

Jack, you raise some valid arguments. I don't think Ned's comment was intended as humour; the accompanying edit summary, and his subsequent vote and justification for deleting seem to indicate otherwise, but of course I could be wrong.

The funny thing is, I don't even think this template should be kept. I went ahead and removed the controversial "odd request" from the template anyway, just so we can focus on the real issue here of whether we need the template or not. I've added my own Delete to the discussion, and toned down some of my previous comments. I appreciate your intervention on this issue. Owen× ☎ 22:31, 7 July 2008 (UTC)

Thanks! The inherently-ordered Japanese edit is great; I've added it to my collection. Since we can prove that some sets cannot be well-ordered, it only stands to reason that some (nontrivial) sets are always well-ordered, right?... Owen× ☎ 01:58, 8 July 2008 (UTC)

Stub types

Hello Jack - You're right - that was an oversight on our part not having any instructions about upmerged templates (it would be upmerged types you'd really need, not redirects). I've added a line to the instructions section of the proposal page. Basically you propose them in exactly the same way as full template/category stub types, but the rules are lenient about the numbers of articles needed. Usually if it's a standard type of split (eg, Nationality-profession-stub), there's no real trouble, but it's worth going through the proposal stage just to be sure. Currently teh mood is against using specific continent-level stubs of this type, but that largely depends on numbers (if there are 20 stubs each from one of 20 different European countries it makes more sense to have a continent-wide stub type). Grutness...wha? 23:57, 7 July 2008 (UTC)

Thanks, I'll do a quick scan and get a shorter list than "all of them" for what countries would be useful. Avoiding continents is probably good, since I think the middle east / southwest asia is completely missing, and there are a ton of ancient and modern guys there. JackSchmidt (talk) 01:52, 8 July 2008 (UTC)

It's probably only going to be useful for ones which have a fair few (certainly 60 isn't needed for an upmerged type, but if something's only ever going to be used on one or two articles it's probably easier simply to put two templates, one for nationality and one for profession). Any that get close to double figures would probably be reasonably worthwhile, though. Grutness...wha? 12:04, 8 July 2008 (UTC)

JRN08

I was trying to archive, but failed. How can I put it in archive if I need down the road? Thanks. JRN08 (talk)

(e/c) No problem. You did it basically, right. Call the page "User talk:JRN08/Archive-2" instead of "Archive-2". Longer reply on your talk page. JackSchmidt (talk) 01:45, 8 July 2008 (UTC)

Thanks.

JRN08 (talk) 01:29, 8 July 2008 (UTC)

Anytime. Thanks for all your stubs! JackSchmidt (talk) 01:45, 8 July 2008 (UTC)

Pages in Category

Thanks for the prompt Jack. I'm about to go test this out :) SunCreator (talk) 22:43, 8 July 2008 (UTC)

It works. Awesome. SunCreator (talk) 22:57, 8 July 2008 (UTC)

Ω

Thank you. I was wondering where the Ω had got to. Sometimes these inserted symbols show up in strange and unexpected places :-) Mathsci (talk) 14:37, 10 July 2008 (UTC)

Essential range

Dear Jack,

If you are not too busy, could you please review the article on the essential range? There are just a few specific questions I have which I will list:

1. I am not sure how to write the mathematicl symbol '+infinity'. The notational problem is that writing L^infinity(μ) can seem confusing to the reader (in my opinion).

2. Also, I do not know how to write g^(-1) (S) for a set S in proper mathematical notation (actually I can write f^(-1) (S); Michael Hardy told me how to do it but I don't know how to write g^(-1) (S))

3. I also think that they are too few links in the article but I am not sure what to link to. If there is nothing much in the article that can be linked to something else, do you think that it is a problem?

Don't worry about editing these things on the article; I can do them if you tell me how to.

Thanks for your help

Topology Expert (talk) 01:22, 11 July 2008 (UTC)

Sure, to get an ∞ just use "&infin;". You can also find one that has been typed somewhere and copy-paste. If you edit this section you'll see the first infinity is written with the & sign, but this one ∞ is just the character itself. It can be gotten from "Show preview" and copy-paste, for instance.

To get g^-1(S) as g⁻¹(S), use "''g''^&minus;1(''S'')".

(generally) An article should link to easier articles near the top so the reader can backtrack if they need to, and should link to a few "more" interesting articles, if they want to keep reading. These are the traditionally useful types (I'm sure you've seen many textbooks that suggest prerequisites at the beginning, and have further reading at the end; this is just the wiki version). Linking to words that might need defining is an old wiki tradition, and a good idea.

(specifically) Essential range looks pretty well wikilinked. I would add a link to real analysis in the first sentence, just because people might not know what measure theory is, though they at least know that analysis is "what comes after calculus".

One math typo: In properties and examples, "The essential range of a function f is always compact. The proof is given in the next section." However, f(x)=x has non-compact essential range. You could add "The essential range of an *essentially bounded* function f is always compact." since this is what is proven in the next section. Alternatively, you could change "compact" to "closed", which is interesting even for non L^oo functions. JackSchmidt (talk) 02:11, 11 July 2008 (UTC)

Anyways, looks good. JackSchmidt (talk) 02:11, 11 July 2008 (UTC)

Dear Jack,

Thanks for your time to review the article. I will follow your advice in the TeX notation and fix up the article tomorrow (or today if I have time). Note that theorem 2 states:

The essential range of a complex valued function, f, defined on a measure space (X, μ) that belongs to L^∞(μ) is compact if μ is an non-negative additive measure.

Actually, by writing that the function belongs to the space L^∞(μ), I am actually stating that the function is essentially bounded (since L^∞(μ) is the space of all essentially bounded functions). I did actually mention this in the section on 'Terminology and useful facts'.

Thanks

Topology Expert (talk) 06:07, 11 July 2008 (UTC)

Dear Jack,

Please ignore the part of my previous post regarding the typo. I now understand what typo you are referring to and I fixed it. Thanks for pointing this out.

Topology Expert (talk) 13:12, 11 July 2008 (UTC)

Dear Jack,

Regarding what you said about changing 'compact' to 'closed', I actually had the same discussion with Oded. Generally, from what I know (and I do not claim that I know a lot about the essential range), the essential ranges of L^∞(μ) functions satisfy stronger properties compared to the essential range of an arbitrary function. I could add that the essential range of any function is closed (and I will), but I think that the essential range should only be defined for L^∞(μ) functions. Later, I may add some more properties of the essential range.

Thanks

Topology Expert (talk) 13:20, 11 July 2008 (UTC)

Thanks II

Thanks for the tips about getting the pages in a category. --KYN (talk) 16:26, 13 July 2008 (UTC)

Differential geometry of surfaces

Hello. I have added an informal introduction to Section 4 and some images (including one of Gauss to the lede from the time he published his research in this area). I'd like the triangulated torus only to move when clicked - do you know how to arrange this? I am still mulling over the intros for sections 5 and 6. Cheers, Mathsci (talk) 13:40, 17 July 2008 (UTC)

I'll look into the image thing. On one's own website this is not too hard—just have two images, one animated and one not, switching between the two on a click. On wikipedia, we have to use the javascript that is already in place. User:Rocchini may be our expert on images, but I don't see an example of this on his page.

Your new introduction to section 4 is great! Also, overall there are a lot more images now, and this is a very good thing. Certainly principal curvature, -0+ curvature, and the Gauss map are very clear. JackSchmidt (talk) 13:51, 17 July 2008 (UTC)

Hello again. I've finished the cleanup with the informal introductions and more images, including 3 mathematicians (all dead). Please tell me what you think and make any improvements that you can think of yourself. The only thing I might still add is a simplified section on connections at the end, taken from Do Carmo, O'Neill and Singer & Thorpe. That way I can probably add a picture of Elie Cartan which is sadly lacking at the moment ... Cheers, Mathsci (talk) 17:44, 23 July 2008 (UTC)

your input

Jack: If you have a moment, could you have a look at this revert which I did and was immediately undone. What do you think? Oded (talk) 01:13, 28 July 2008 (UTC)

Your revert looks fine to me. You could have suggested he add it to the talk page, but since it was his first edit, it was not too likely to help. Directing him to WP:COI is the right thing to do. WP:EL also has a COI section. The simple summary of them is: don't add external links to websites associated with yourself, rather mention them on the talk page and ask if they would be good additions. It allows a limited form of advertising without cluttering the articles. JackSchmidt (talk) 04:32, 28 July 2008 (UTC)

Rotation matrix/Eigenvector slew merger

Rotation matrix, version 11:31 31 July 2008, is a suitable merger.

But unfortunately there is some Gurch!!

Stamcose (talk) 12:31, 31 July 2008 (UTC)

Thanks

Thanks fo ryour tip on contesting blocks. I had trouble searching for an easy way to contest a block. (Actually, aince she blocked my IP address, I could not even try to do what you suggested.Dogru144 (talk)

Undated message from 2008-07-12. JackSchmidt (talk) 16:36, 14 January 2009 (UTC)