Talk:Ellipse/Archive 1

Probably this picture could be used: [1] (Fig.207), see [2]. Boris Tsirelson 05:12, 2 May 2010 (UTC)

I added two pictures from that source. Incidentally, feel free to change/adapt/add stuff, CZ is a wiki, you know. --Paul Wormer 12:08, 2 May 2010 (UTC)

trammel, figs.

1. I have doubts about fig.2; it seems to me that the central line should overlap with the red and the green ellipsi, until their centers.
2. I like the deduction of the Trammel. Who was Trammel? What century, what country did he/she live?
3. How about to borrow the animation of the trammel device grom wikipedia; I mean, http://en.wikipedia.org/wiki/File:Bsgrinder.gif ?
4. As for the drawing with a string... I used the loop to draw ellipsi; then the whole ellipse can be drawn at once. (The lenth of the string should be extended with a piece of length equal to the distance betwin the focuses.)
Dmitrii Kouznetsov 18:30, 2 May 2010 (UTC)

Dmitri, I'll try to follow your advice on fig. 2 later today. I made it with Autocad and have no code. If you can make a better picture I would appreciate it. Look in an English dictionary for trammel, it is not a person. (I didn't know the word either). We are not allowed to use animated gifs, or using stuff from Wikipedia. Material from WP is only allowed if the real name of the author is known and we have written permission. With regard to the loop: I followed the description and the picture in the book. Boris suggested that I include the picture and I wrote the text to match it.

I have a question to the mathematicians: two things are missing. The quadric Ax²+Bxy+Cy²+Dx+Ey+F=0 and the definition by means of directrices (vertical lines at fixed distance from foci). Is that bad?--Paul Wormer 06:13, 3 May 2010 (UTC)

Ah, now I can answer, since Peter gave appropriate terms. I believe, these are medial gaps! (That is, less than major gaps, but larger than minor gaps.) But I must admit, this classification is not uncontroversial. Boris Tsirelson 14:48, 3 May 2010 (UTC)

A trammel point is also a woodworking guide that attaches to a router (tool) to cut elliptical holes. It's actually a little misnamed, as it physically consists of several pieces, such as an anchor point, guide arm, and attachment to the cutting tool base. Howard C. Berkowitz 14:54, 3 May 2010 (UTC)

Approvals etc

Let me express my opinion, probably quite controversial.

0. It is not the question, "is it bad?"; it is THE question, "should the article be approved?".

1. The approval mechanism is THE feature of CZ. We should not dream of Google juice when our articles are "unapproved, subject to disclaimer, not to be cited".

2. Unfortunately, in order to approve advanced math articles we need many (20..100) active math editors (then it will be reasonably probable to find at least two editors competent in the favorite matter of an author).

3. Fortunately, in order to approve undergraduate math articles it is enough to have just two active math editors, provided that... see (6) below.

4. Two necessary conditions for approval: (a) not misleading; in math context it just means, no errors; and (b) useful.

5. Desirable but NOT NECESSARY, and in fact not reachable: unimprovable. It is always possible to add something, or make a small improvement. "Useful" does not mean "as useful as at all possible". I understand that in a political context, to miss some aspect may be an intolerable bias. But in math context this is not an issue. Some aspect is missing? Well, work on it AFTER approval, if you can and want.

6. Thus, I call math editors to strive to approve articles (satisfying the two necessary conditions), not to find a reason to delay the approval.

A1. Regretfully, today we have at most two active math editors: Peter Schmitt‎ and Dmitrii Kouznetsov. (I would be happy to be wrong in this point.) I've asked both about possible approval of "Ellipse". One did not reply (yet), the other made some remarks.

A2. I can apply for the editor status, if I'll feel that this will help. That is, if at least one existing editor will support my attitude expressed above.

Boris Tsirelson 11:15, 3 May 2010 (UTC)

By the way (off-topic), my attitude to refereeing journal articles is similar: a referee should point out errors and minor, evident improvements. However, a substantial improvement is a business of authors. The referee can (if needed) write a subsequent article later (being already an author, not a referee). Boris Tsirelson 11:26, 3 May 2010 (UTC)

Boris, I'm somewhat puzzled by the fact that your general comments are on this particular page. The forum would be a better place for your thoughts.

I gave this article level 2, which means that it is (IMHO) not yet ready for approval. Further, I did not know that you're not a math editor, my question to the math editors was also directed to you. Do I understand from your above comments that in your opinion the directrix and quadric don't need to be added to this article?

Finally, one editor is enough to approve an article, so if you become an editor you can approve any math article you want.

--Paul Wormer 12:19, 3 May 2010 (UTC)

Really, by one editor?! Did I miss a major change of the rules? Or did I misunderstood the rules from the beginning? Boris Tsirelson 14:33, 3 May 2010 (UTC)

Why here and not on a forum? Because we have no math forum (WP has, by the way). And the "general" forum is too verbose for a mathematician... Sorry Paul, here by "mathematician" I mean everyone contributing to math articles. Boris Tsirelson 15:11, 3 May 2010 (UTC)

By the way (off-topic), my attitude to refereeing journal articles is similar: a referee should point out errors and minor, evident improvements. However, a substantial improvement is a business of authors. The referee can (if needed) write a subsequent article later (being already an author, not a referee). Boris Tsirelson 11:26, 3 May 2010 (UTC)

(edit conflict: written parallel to Paul's comment)

On the whole, I agree with you, Boris. With (4) I would also include: (c) and there are no MAJOR gaps (meaning: all top "level topics" are at least mentioned; drastic example: prime number without: there are infinitely many, and factorization of natural numbers). Unless you include this already with (b), usefulness.

As for your item (5), I have to admit that I thought about some additions to Paul's text (instead of thinking about approval), but when I read your message this night (even before reading this), it occured to me that, in this case, it might be better to approve first and then make changes.

I, and -- if I remember it correctly, Paul too -- are not so much concerned with approvals, one reason being that (re)approval of approved but extended aricles is not easy to do under the current rules with a lack of non-involved editors.

Another difficulty is that even minor changes (clarifications of wordings, etc.) are likely to be classified as "adding content" instead of mere "copy editing". (If you want to see an example for this, then you will find it on the talk page of Complex number. I hope that these rules will be revised some time in the future.) Having three editors would change this radically because then (even) all three may have contributed content AND were allowed to approve the article.

Peter Schmitt 12:45, 3 May 2010 (UTC)

Peter, I am glad to see that our views are rather close. About (c), I agree. About a number of inconveniences caused by approval, I believe that we should be patient to them, since, I believe, approval is very important for survival of CZ. Boris Tsirelson 14:40, 3 May 2010 (UTC)