User talk:Fly by Night

This user is a proud Englishman

Welcome!

Welcome!

Hello, Fly by Night, 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:

• The five pillars of Wikipedia
• Tutorial
• How to edit a page and How to develop articles
• How to create your first article (using the Article Wizard if you wish)
• Manual of Style

I hope you enjoy editing here and being a Wikipedian! Please sign your messages on discussion pages using four tildes (~~~~); this will automatically insert your username and the date. If you need help, check out Wikipedia:Questions, ask me on my talk page, or ask your question on this page and then place {{helpme}} before the question. Again, welcome! AlexHOUSE (talk) 21:02, 20 January 2010 (UTC)

Deletion tags

Sorry I didn't get to you earlier (dealing with a virus). {{db-talk}} does mark talk pages that don't have articles for speedy deletion. A bunch (I think all) of the speedy deletion tags are listed at Wikipedia:Speedy deletions. Another useful section is Wikipedia:Template messages. Ian.thomson (talk) 19:09, 21 January 2010 (UTC)

No problem, I understand. I went out on a limb and posted it anyway. It seemed to have worked and the page was deleted. I had no idea there was so much depth to Wikipedia. I thought it would just be about writing articles. It seems that there's a richness of politics and bureaucracy too. Fly by Night (talk) 12:48, 22 January 2010 (UTC)

AWB

Hi. I replied to my talk page. :) -- Magioladitis (talk) 09:19, 7 February 2010 (UTC)

I just noticed that this filed in the infobox doesn't affect only the title on the top but the name displayed on the map. Maybe you should go to Template talk:Infobox UK place and request the name on the map to be bolded too. -- Magioladitis (talk) 10:42, 7 February 2010 (UTC)

Grid refs

Please don't put non-breaking spaces into OS grid refs - they cause the wrong coordinates to be generated. See Talk:Jumbles Reservoir#Grid refs, click on the examples I have given. The correct form is two letters and then four, six, eight or ten digits (depending on whether the accuracy is to be shown to 1 km, 100 m, 10 m or 1 m), with no spaces or punctuation. --Redrose64 (talk) 14:22, 7 February 2010 (UTC)

The UK Grid Reference Finder site [1] generates the grid reference with spaces. This is the correct way to display the coordinates. It seems to be a problem with Wikipedia that it can't handle the spaces. •• Fly by Night (talk) 14:25, 7 February 2010 (UTC)

It does generate them with spaces - but spaces (whether non-breaking or normal) cannot be handled by the Wikipedia templates which permit an Ordnance Survey grid reference. There is documentation on valid forms of grid ref at {{Oscoor}}, this template being the last stage within Wikipedia before the grid ref is passed on to an external site for further processing. I cannot control how Wikipedia/that site handle grid references: if you believe that the inability to handle spaces is a bug, I suggest taking it up at Template talk:Oscoor; it may well be a limitation within the external site. --Redrose64 (talk) 15:00, 7 February 2010 (UTC)

Thanks for the information, Red. •• Fly by Night (talk) 15:04, 7 February 2010 (UTC)

OK, any time. I see from your contributions a high proportion of articles concerning Bolton and your first article was Tonge, Greater Manchester. Did you know I used to live in Bolton? --Redrose64 (talk) 15:29, 7 February 2010 (UTC)

Really? It's a small world :-) Thanks for your help, I'm new to Wikipedia. I look forward to working with you in the future. •• Fly by Night (talk) 16:58, 7 February 2010 (UTC)

Yep. Lowton House (School Hill estate); Shrewsbury Road; Hilden Street; Bury Road; Montrose Avenue. --Redrose64 (talk) 17:32, 7 February 2010 (UTC)

Reservoirs and places

Hello Fly by Night,

Thanks for your contributions on places straddling the West Pennine Moors. Just a nudge that reservoirs should use {{Infobox lake}} and country parks, {{Infobox park}}. I converted the Jumbles Reservoir with this change, but it will need further input. You may need to check through your contributions in the last few days to ensure the right templates are used. Thanks again, --Jza84 |  Talk  18:51, 7 February 2010 (UTC)

Thanks a lot for the advice. I didn't know there were different infoboxes. I can't get the river one working. There seems to be some convention for the conversion of coordinates, e.g. (53.6253,-2.4025) became {{coord|53|37|31|N|2|24|9|W|region:ZZ_type:waterbody|display =inline,title}}. I have only written three reservoir articles, and you've alreay corrected one of them. I would really appreciate the help of such an experienced user as yourself. Could you please help me by making the changes? I promise to study the changes. The other two were Wayoh Reservoir and Turton and Entwistle Reservoir. •• Fly by Night (talk) 19:06, 7 February 2010 (UTC)

Hello there! We had a slight edit clash then - I think we posted one-another at the same time! :)

You seem very keen on Wikipedia, which is refreshing. It is good to see new editors joining up, particularly from the North West! I'm not sure if your on the urban or rural side of things, but we have the Wikipedia:WikiProject Greater Manchester, the Wikipedia:WikiProject Merseyside, the Wikipedia:WikiProject Cheshire, and (the one which I suspect you will be interested in from your contributions) the Wikipedia:WikiProject Lancashire and Cumbria. These are kind of like forums, or communities of editors who can share interests, goals, experience and advise - they are very good for getting input and/or solving problems.

I can't promise I'll get through them all (especially unlikely tonight), but I'll do my best to have a wizz through your additions and try to catch the basic infobox swaps where I can. Feel free to join one (or more) of our local WikiProjects in the mean time - I'm sure you will be welcomed warmly. Thanks ever so much again for your contributions - they are important articles that have been overlooked for too long. --Jza84 |  Talk  19:20, 7 February 2010 (UTC)

Thanks very much for your warm welcome. I appreciate it. I shall try to join some of these pages that you've suggested. •• Fly by Night (talk) 19:32, 7 February 2010 (UTC)

<-Hello! Just had another clash!

With regards to the WikiProject importance scale, Wikipedia:WikiProject Greater Manchester/Assessment is the most comprehensive resource on the matter, but in short, it's mostly a subjective decision. The importance of the article can be determined by any editor, but common sense, consensus and the assessment guidelines are elements that can be considered.

To be truthful, I hadn't noticed I'd used mid for one, and low for another - I'd say the parks straddle the mid to low importance line and I wouldn't oppose any change (I trust your judgement entirely). Also, it doesn't mean the article is not important or that the edits are not valued, its more to do with prioritising editing time and objectives for the WikiProject's team. Does that help at all? --Jza84 |  Talk  19:37, 7 February 2010 (UTC)

That does help, thanks. I'll try and read the link you gave me. Could I come back to you if I were to need any clarification? I wouldn't even think about changing any of the ratings: I'm still finding my feet around here. I appreciate your patience and the help you're giving me. Sorry to be such a nuisance. •• Fly by Night (talk) 19:45, 7 February 2010 (UTC)

Of course you can - that's no problem at all. You're doing great! Much much better than I was doing at your stage in editting! The relevant WikiProject would be the better option though for all queries, especially if I'm not able to get back to you quickly. --Jza84 |  Talk  20:04, 7 February 2010 (UTC)

My motto seems to have become "Copy and paste, paste and copy." I was doing alright with the UK infobox. That's why I've found the river one so hard to use: I need an example to "Copy and paste, paste and copy." :-) •• Fly by Night (talk) 20:07, 7 February 2010 (UTC)

When I create an article, I try and pop one or two relevant WikiProject banners on its talk page straight away. Choosing suitable ones can be difficult: but for a fixed subject - a village, reservoir, park etc., a subject-related banner and a geographical banner are usually adequate. It's not a bad idea to find an existing article dealing with the same subject, and in the same area, and pinch the banners from that. One thing to be careful of is not to apply an inappropriate importance or class. I believe that it's fairest if I didn't assess my own contributions, so when copying a banner, I blank out class and any importance parameters, and remove all the other parameters except those which are obviously correct. So, if I were writing (say) Bromley Cross railway station (which already exists), then I'd look at Talk:Bolton Interchange, which has these:

{{TrainsWikiProject|UK=yes|stations=yes|class=start|UK-importance=low|importance=low|unref=yes|imageneeded=no}}

{{WikiProject Greater Manchester|importance=Mid|class=start}}

so on Talk:Bromley Cross railway station I would put:

{{TrainsWikiProject|UK=yes|stations=yes|class= |UK-importance= |importance= }}

{{WikiProject Greater Manchester|importance= |class= }}

After a while somebody else will come along and assess it for importance and class. --Redrose64 (talk) 20:10, 7 February 2010 (UTC)

Sorry for the late reply; I went to cook after my last post. Thanks for the tips. I'll try to put banners on all of my new articles. And if I can't find the right one then I know who to ask. •• Fly by Night (talk) 17:38, 8 February 2010 (UTC)

Your recent edits

Hello. In case you didn't know, when you add content to talk pages and Wikipedia pages that have open discussion, you should sign your posts by typing four tildes ( ~~~~ ) at the end of your comment. You may also click on the signature button located above the edit window. This will automatically insert a signature with your username or IP address and the time you posted the comment. This information is useful because other editors will be able to tell who said what, and when. Thank you. --SineBot (talk) 19:46, 10 February 2010 (UTC)

But I have been signing my posts. •• Fly by Night (talk) 19:47, 10 February 2010 (UTC)

Wayoh Reservoir

Hi, I've no objection to you removing the category. See my comment on the article talk page. All the best. NtheP (talk) 08:58, 12 February 2010 (UTC)

Harmonic differential

I made some style changes to your article harmonic differential, and I had some comments that may make article editing easier for you in the future. You may not know about the templates {{nowrap}}, {{nowrap begin}}, and {{nowrap end}}, but they make non-breaking spaces much easier to read. Usually we don't use periods for multiplication; instead we use nothing or we use ·. The HTML entity   inserts a small space which is very useful for spacing differentials. We don't usually italicize Greek letters: ω, not ω. You can find all of this at Wikipedia:Manual of Style (mathematics).

Finally, I noticed that you prefer to write differentials with a roman d (as in dx, not dx). Where did you learn this? I've only ever seen this done on Wikipedia, and I'm curious to know where it comes from. Ozob (talk) 04:11, 22 April 2010 (UTC)

Thanks for the improvements to the article, and thanks for the template tips. I'll make sure to use them soon. As for the Roman and italic d, it's just a matter of style. Some people write dx because the think of d as an operator, and the operator is applied to x. Others write dx because they treat dx like a variable in some sense, and ignore the idea of d as an operator. The Royal Society Proceedings Series A (Mathematical and Physical Sciences) have a style file (rspublic.cls) to be used in all of its published articles that specifically defines a macro to use for the differential which uses a Roman d: \newcommand{\rd}{\mathrm{d}} %Roman d for differential. •• Fly by Night (talk) 18:39, 22 April 2010 (UTC)

Ah! Hmm. On the other hand, they also suggest a Roman i for the imaginary unit and a Roman e for the base of the natural logarithm. I'm not aware of anyone using either of those. The relevant style guideline here is probably WP:RETAIN, which tells me that I can't edit an article specifically to change dx to dx, nor can you edit it to go the other way; the style may be changed only for consistency's sake. (I should mention that I usually think of d as an operator, the exterior derivative, but I still prefer it in italics: Most single letter operators are written in italic, as in f, g, T, and so on.)

But you weren't aware of anyone (outside of Wikipedia) using a Roman d for differential, so there's no reason to assume that you would be aware of any other notational conventions. •• Fly by Night (talk) 18:55, 27 April 2010 (UTC)

I prefer raised asterisks because they're semantically correct and because in the right font an unraised asterisk will give an expression that does not make sense, such as $\omega *\,$. But of course they compromise the beauty of the expression. I don't think there's an established rule for this one, but I'll defer to you for this article since you're its first major contributor. Ozob (talk) 04:39, 23 April 2010 (UTC)

If I were to have used LaTeX coding, i.e. <math></math> then I would have used the command \omega^*, but I didn't, I used HTML, so I used ω*, instead of the ω^* (ω^*) which you prefer. I don't know why you decided to arrive on my talk page and start nit picking; but I'd prefer that you left me in peace to edit. Article talk pages are the place for this kind of talk. Thank you. •• Fly by Night (talk) 18:55, 27 April 2010 (UTC)

Vector Calculus

Hello,

First, thank you for taking the time to give a detailed response. Unfortunately your post used quite a few terms that I'm unfamiliar with, so I just wanted to clarify what I understood from what you wrote. Basically, as I see it, there are two functions so to speak associated with f; one that maps the origin of the vectors (so f(0,0,0) = (1,1,0)), and another one which adjusts the the tangent bundle at each point (the differential?). Is this at all right? Probably not...I'm sorry for being a little slow, it's just that none of this (tangent spaces, fibre bundles, etc.) have been mentioned in my textbook thus far, and all the functions that I've dealt with take a vector as its imput and produce an imput, without concern for the origin (aka vector fields). Should I be more familiar with Linear Algebra before studying Vector cal? I sort of just picked up some textbooks to read over the summer, and I guess I didn't pay too much attention to what the prerequisite knowledge was.

At any rate, there's a partial solution at the end of the book. It's not very descriptive, but it seems to involve less alien terminology...perhaps you can make some sense of it. It goes as follows:

"Let g₁ and g₂ be C¹ functions from R³ to R such that g₁(x) = 1 for |x| < 2√2/3; g₁(x) = 0 for |x| > √2/3; g₂(x) = 1 for |x - (1,1,0)| < √2/3; and g₂(x) = 0 for |x - (1,1,0)| > 2√2/3. Let $h_{1}(\mathbf {x} )={\begin{bmatrix}1&0&0\\0&-1&0\\0&0&0\end{bmatrix}}{\begin{bmatrix}x_{1}\\x_{2}\\x_{3}\end{bmatrix}}+{\begin{bmatrix}1\\1\\0\end{bmatrix}}$ and $h_{2}(\mathbf {x} )={\begin{bmatrix}0&0&-1\\0&0&0\\0&0&1\end{bmatrix}}{\begin{bmatrix}x_{1}\\x_{2}\\x_{3}\end{bmatrix}}$ and put f(x) = g₁(x)h₁(x) + g₂(x)h₂(x).

I don't really understand why this works, or how it even resolves my dilemma regarding the whole origin problem. It seems to me like a vector is inputed, and a vector comes out. Anyways, maybe you can clarify what the solution means. Thanks a lot! 173.179.59.66 (talk) 18:20, 26 June 2010 (UTC)

Let's think of a concrete example of a map ƒ between ℝ³ and ℝ³, i.e. ƒ : ℝ³ → ℝ³. So for every p ∈ ℝ³ we have ƒ(p) ∈ ℝ³. At each point p ∈ ℝ³, the tangent space to ℝ³ at p, denoted by T_pℝ³, is the vector space of all vectors based at p. A vector based at p is a member of the tangent space T_pℝ³. Now, let's say that ƒ(p) = q. We can consider the tangent space at q, namely the vector space of all vectors based at q. So we have all the vectors based at p, denoted by T_pℝ³, and all the vectors based at q, denoted by T_qℝ³. What dƒ_p does is take a vector based at p and gives a vector based at q. It is a linear map between vector spaces. We have dƒ_p : T_pℝ³ → T_qℝ³. The tangent bundle of ℝ³ is an affine space.

I'm not sure I follow your solution either. Let x = i + j + k as you stated in your original problem. In other notation: x = (1,1,1)^T. Then g₁(x) = 0 since |x| = √3 > 2√(2/3). Furthermore g₂(x) = 0 since |x – (1,1,0)| = |(0,0,1)| = 1 > √(2/3). So ƒ is just the zero map.

If I were you then I would definetly brush up on your linear algebra. It's a basis for many things, and vector calculus is a next step after learning linear algebra. Also, try to read the affine space article. If you've made a mistake with copying the solution then come back to me; or if you work it out then come back to me. I would be pleased to hear how you get on... •• Fly by Night (talk) 19:53, 27 June 2010 (UTC)

First, yes you were right, I did make a mistake. It should read "g₁(x) = 1 for |x| < √2/3; g₁(x) = 0 for |x| > 2√2/3". I'm not sure if that changes any of your explanation.

Second, after reading your description I think I've come to understand the problem...at the very least, I've understood that I should study linear algebra! I still have one qualm though. My textbook claims that no prior knowledge of linear algebra is necessary (vectors and basic matrix operations are defined in the introduction). And I've scoured the index for any mention of tangent bundles, affine spaces, etc., to no avail. And thus far, without exception, all the maps I've encountered have been of the form f:R³ --> R², (x,y,z) --> (e^xz, xy), or something like that. This example seems so far removed from anything that was done in the textbook so far. This leaves me with two question: 1) Is there a way to look at this problem with more elementary knowledge, in a way that should be expected of me? 2) Will I have to relearn vector calculus after studying linear algebra? Thanks a lot, you've been a lot of help. 173.179.59.66 (talk) 02:44, 28 June 2010 (UTC)

There won't be any mention of tangent bundles or affine spaces in you book; it's an elementary text after all. These are generalisations. Like I said: the set of all vectors based at a point in ℝ³ is the tangent space to ℝ³ at that point. All of the tangent spaces collected together form the tangent bundle. Talking in terms of tangent spaces and tangent bundles isn't necessary to solve your problem; in fact it seems to more of a hindrance. These tangent bundles are a generalisation that apply to many more circumstances than just ℝⁿ; they apply to manifolds. I was hoping to get you to understand what you were doing when you were solving the problem, and not just how to solve the problem.

You don't need to learn linear algebra is you want to follow the book, do the sums and get the answers. If you want to have an idea of the bigger picture then a knowledge linear algebra would be an asset. Linear algebra is all about vector spaces and matrices, so it would obviously come in handy when doing vector calculus! I think the problem is that I've tried to explain things in too broad of a context, and for that I apologise; I think I've just confused things more than help them. So I'm sorry.

Just as a parting example consider your map ƒ(x,y,z) = (e^xz, xy). This takes the (0,1,0) to (1,0). The Jacobian matrix evaluated at (x,y,z), denoted by J(x,y,z), is the matrix of the differential:

$J(x,y,z)=\left({\begin{array}{ccc}ze^{xz}&0&xe^{xz}\\y&x&0\end{array}}\right)\ \ {\mbox{and so}}\ \ J(0,1,0)=\left({\begin{array}{ccc}0&0&0\\1&0&0\end{array}}\right).$

Let's pick a vector based at (0,1,0); say (1,2,3). The image of the vector (1,2,3) is then

$\left({\begin{array}{ccc}0&0&0\\1&0&0\end{array}}\right)\left({\begin{array}{c}1\\2\\3\end{array}}\right)=\left({\begin{array}{c}0\\1\end{array}}\right).$

So ƒ takes the vector (1,2,3) based at (0,1,0) in three-space to the vector (0,1) based at (1,0) in two-space. •• Fly by Night (talk) 19:13, 28 June 2010 (UTC)

OOOHHH okay now I see what you mean.

Alright, I understand the math, but I am ever so confused about the notation. You see, my book said that if f: Rⁿ --> R^m, f is vector-valued and takes x to produce an m-tuple (f₁(x), ... , f_m(x)). So I thought that (f₁(x), ... , f_m(x)) itself was a vector (it's called vector-valued after all), but from what I've understood you're saying it's a point, and the vector at a point is the tangent to that point...so why do they call it vector-valued??? And why do they call it the vector emanating from wherever instead of the tangent vector emanating from wherever???(Sorry for the pestering questions, you must be pretty annoyed at me...but I feel like I'm at the precipice of understanding everything). 00:17, 29 June 2010 (UTC) —Preceding unsigned comment added by 173.179.59.66 (talk)

Don't be silly; you're not annoying me at all. Vectors and points are more or less interchangeable. Your book is treating ℝ^{n like a vector space, and each of its points as Euclidean vectors in that vector space. I think the idea is to get you away from thinking that a function takes a number and gives a number. A vector valued function (with the real line as its domain) takes a number and gives a vector, i.e. a point in n-dimensional space. To get to a point in space you travel in a given direction a fixed distance. But that's just what a vector is: something with direction and size. So for any point p in ℝn we get a vector: the vector based at the origin and ending at p. Likewise, for any vector based at the origin we get a point in ℝn: the point at the end of the vector. It's not so clear what we do with vectors not based at the origin. But the Affine Space article tries to examine this, albeit in an axiomatic way. Take a look at the article Vector Valued Function for some more details. •• Fly by Night (talk) 19:12, 30 June 2010 (UTC)}

Great, thanks a lot, I understand now. You were a lot of help! 70.52.45.181 (talk) 03:30, 1 July 2010 (UTC)