User talk:Paolo.dL/Generic

This archive contains personal messages which are not related to the content of my open letter.

Paolo.dL 11:16, 1 August 2007 (UTC)

Request for edit summary

It would be nice if you could use the edit summary more often, it helps others understand what you do. Thanks. You can reply here if you have comments. Oleg Alexandrov (talk) 03:02, 1 August 2007 (UTC)

You are right, I am aware of the importance of the edit summary. I apologize for forgetting too often. Paolo.dL 09:21, 1 August 2007 (UTC)

Integral

Hi, Paolo!

I have reinserted the material (fundamental theorem of calculus) you recently deleted from this article. My reasoning is that this section of the article was inserted after a number of editors had discussed the issue at length, and had decided that this is important information that should be included. In other words, your judgment runs counter to the consensus of interested editors.

Quite a few people have put a lot of time and effort into this article. If you want to make major changes to the article – and especially if you want to delete whole sections of it – it would probably be a good idea to propose the changes you want to make on the talk page and see what other editors think before just popping your changes in there.

Thank you. Have a great day! DavidCBryant 20:11, 9 August 2007 (UTC)

Thanks for writing back, Paolo. I put my response on my talk page. DavidCBryant 12:50, 10 August 2007 (UTC)

Not a UI bug (?)

Although as others have said there was some newbie biting and irrational assuming of bad faith going on here, Matthews deliberately chose to block just your username and not your IP - both features are provided by the Mediawiki interface and it doesn't make sense to attribute this to a UI bug. We tend to err on the conservative side of not blocking entire IPs because other users might be using them and we don't want to block others inadvertently. Your action of creating a new account was not unreasonable - or even against the rules - if it was not used to continue the disruptive action. Dcoetzee 00:36, 25 August 2007 (UTC)

The bug I described is completely different from the non-bug you described. I have never suggested nor implied that Matthews should have blocked my IP, but that MediaWiki should have blocked automatically my new user account created from my blocked IP! :-)

I will soon archive this section. I don't want this letter to become too long. I consider misinterpretations and ensuing explanations to be personal messages, which other readers are obviously not interested to see. Thanks anyway for sharing your opinion. Regards, Paolo.dL 21:44, 26 August 2007 (UTC)

Oh, my mistake - I didn't think it was possible to even create any user account from a blocked IP. Thanks for your response. Dcoetzee 04:56, 27 August 2007 (UTC)

Refactoring

I have deleted some sentences that really were not needed, as a form of mild refactoring to enhance readability. I understand now the reason why you explained the concepts of injection, surjection and bijection in such detail! You probably thought I was stupid and you had a good reason for believing it! :-) But these explanations of elementary concepts make the discussion too long and I am sure none of the readers or contributors to this discussion need them. Consider that we have very nice articles on Wikipedia about these concepts. I think that now your main and more interesting points became more visible. If you don't like the idea, please just undo my refactoring, or restore your sentences in a separate subsection called, for instance, "Definitions of injection, surjection and bijection". Otherwise, please just delete this sentence and start a new section about our first step. Thanks, Paolo.dL 20:02, 21 September 2007 (UTC) (from Talk:Inverse function).

Yes, I'm perfectly happy with your refactoring, though I added a short warning note at the point that the material was removed. The long explanation was just intended to clear up the miscommunication that we seemed to be having.

By the way, I've taught enough math classes and talked to enough people outside of my area to know the difference between stupidity and simple confusion. My current impression of you is:

1. You are obviously quite smart.
2. You can be somewhat stubborn, probably because you are used to being right about things.
3. You care a lot about making this article more coherent.

I would venture to say that I have the same three qualities. ;-) Jim 21:05, 21 September 2007 (UTC)

Thanks a lot for your kinds words. Yes, I agree, I guess you are very smart, stubborn and constructive as well, and a good mathematician, but we use our mind in different ways. We will probably be able to do a good job together, and with the help of KSmrq, which is one of the best writers in Wikipedia:WikiProject Mathematics, in my opinion! Paolo.dL 21:12, 21 September 2007 (UTC)

Your comments at Talk:Function (mathematics)

Hi Paolo, I am very disappointed in you after the recent comments you left there. If you step back and reread them in a disinterested way, you will see that they constitute a personal attack against another editor, Ksmrq. I am aware that the two of you have had disagreements in the past. I can even see how you may feel vindicated by his adopting some of your ideas and incorporating them into his edits. But I draw diametrically opposite conclusions from that: far from being dismissive of you, Ksmrq patiently worked to adopt some of your proposals, in spite of himself (that requires quite a bit of grace!); by contrast, you appear to use Ksmrq's good will as an opportunity to mock him and instead of using this opening to re-establish good faith and resume much needed joint work on improving the article, you just childishly revel in crowing "I told you so". This is very obnoxious of you and will likely result in people refusing to listen to your suggestions in the future, even if they be made in good faith.

I believed for a while that you were polite and interested in bringing Wikipedia articles up to higher standards, but maybe I should reconsider now. In any case, take my advice and remove or cross out your uncivil comments. Best, Arcfrk 00:20, 11 October 2007 (UTC)

I am interested in that indeed, but I can't give my contribution if KSmrq keeps behaving as the owner of the articles related with mathematics. Please see my complete answer on User talk:Arcfrk. Paolo.dL 11:39, 11 October 2007 (UTC)

Your experience Is Not Unusual

I have put this message on the Centrifugal Force talk page several times and it was deleted by the editor vandals of the police force who like to hit delete before they think. Message follows: Poalo. Wake up. What they are telling you is that your opinion is not going to be allowed on Wikipedia. From the way they treated David Tombe, it is clear that if you have a physically valid and reasoned logical argument that proves them wrong, they simply block you and delete your edits. They don't allow disagreement no matter how correct and logically reasoned it is. David Tombe obviously knew what he was talking about so they had to block him. Wake up and realise that they will never let you change anything they write. These guys are not nice, and they will never agree with your ideas even though you obviously know more and understand physics much better than they do.

It is apparent from this that you already have some experience with the tuggery of wikipedia editors. i thought i might warn you about the nasty characters you will meet when you discuss physics. But i see from the above new are not exactly a babe in the woods. Bottom line is that you are just fresh meat for the tugs and they love blocking people after they exasperate you and fustrate you by playing nice when they really are not nice and will stab you in the back at the first oportunity. This is what they do to anyone who openly questions the official wikipedia party line. I hope you know this by now, so you will not be the lamb going to the slaughter.72.64.53.108 (talk) 21:24, 3 July 2008 (UTC)

Translation with no acceleration

On Talk:Centrifugal force you wrote:

"Just do a coordination translation to everything in the eccentric frame so that the origin now rests on the rotation axis. Since a translation doesn't change any accelerations you have now created the same situation as the article covers."...

A translation may change acceleration. In this case, it doesn't because the position of the new origin, as seen from the old frame, (i.e. the translation vector) is fixed, i.e. time-invariant.

Yes, precisely, you can generalise; that's partly why this class of accelerated reference frame is important.- (User) WolfKeeper (Talk) 21:46, 15 July 2008 (UTC)

In the case of a particle moving along an S-shaped path, or any non-circular and non-rectilinear path (this is the situation described in the article, isn't it?), the translation vector is time-variant, and it has non-null second derivative.

No. The translation vector is due to the reference frame origin being offset from the rotation axis for the frame. Any particle who moves within the reference frame has nothing whatsoever to do with it; the *translation* is a fixed coordinate mapping for the entire frame.- (User) WolfKeeper (Talk) 21:46, 15 July 2008 (UTC)

Believe me, there's no way to give an answer to my question using just mathematics. For instance, in the article about fictitious forces, in the example about orbiting (but not rotating) frames, you have a situation in which it becomes clear that the fictitious force that we conventionally call "centrifugal" actually appears in the orbiting frame as a uniform force field (every point in the orbiting frame is acted upon by the same centrifugal force), rather than radial! It appears clear that calling this force centrifugal is just an arbitrary decision. You might very well call it "universal force" or whatever. This is yet another example in which what we call centrifugal force does not depend on position.

I'm sorry I don't understand. The centrifugal force in the rotating frame of reference is radial, and varies proportional to distance from the frame rotation axis, which is chosen for greatest convenience to be at the centre of mass of the system of bodies, it's not the same everywhere.21:46, 15 July 2008 (UTC)

Math just tells us we have a fictitious force. We all know how to compute this force, but formulas give us a number, they don't give us a name for that number. The problem is just how you decide to call it (and of course, how the scientific community agreed to call it by convention).

It's easy for us. We look at the reliable sources and use that.- (User) WolfKeeper (Talk) 21:46, 15 July 2008 (UTC)

Now, according to you, PeR, and Brews, the world agreed to call it centrifugal; I am not 100% sure that all authors agree about that, but I actually don't care, as long as you all agree! And I am glad we can simplify our task by adopting a conventional answer on which we all agree.

There certainly are multiple definitions of the term 'centrifugal force' as with a great many terms. This particular article is about the term that applies to rotating reference frames that seems to be currently the most common usage of that term. That commonality of usage wasn't true in the past, and for all we know, may or may not be in the future.- (User) WolfKeeper (Talk) 21:46, 15 July 2008 (UTC)

Does all of this make sense to you? Paolo.dL (talk) 20:25, 15 July 2008 (UTC)

Not completely....- (User) WolfKeeper (Talk) 21:46, 15 July 2008 (UTC)

Total functions and partial functions

Hey, I just saw your discussion in talk:partial_function. I understand and sympathize with your confusion and dissatisfaction, but the usage is quite standard, and appears in such other analogous ways as the usage in order theory, where one particular subtype of the partial orders is the total orders. When mathematicians use partial in this way we don't mean "incomplete." By analogy, consider this conversation between friends:

• "Could you spare ten minutes to help me move some furniture?"
• "No, I could spare two hours to help you move some furniture."

The second friend's reply would strike most people as odd. Of course the requester could have denied his friend the opportunity to behave so strangely by being more explicit:

• "I'd like your help in moving some furniture. Do you have at least ten minutes available (not that I would dream of using more than the ten I've specified)?

but that feels cumbersome to specify in such detail. In the same way, if a colleague asked me "Are the real numbers partially ordered by the less-than relation?" my answer would be an emphatic "Yes." I might even reply, "Yes, in fact less-than is a total order on the reals." Another analogy: if a friend advises you, "This is your twenty-fifth anniversary, you should give your wife a decent gift," would you interpret her to be counseling against giving diamond earrings because that's too nice a present?

As to your dissatisfaction with this usage, I offer the observation that in producing dictionaries lexicographers long ago gave up trying to prescribe usage and came to understand that a more appropriate role for them is to describe it. Likewise, when people come to Wikipedia, they want primarily to understand the language that is in fact used.

Hope this helps.—PaulTanenbaum (talk) 06:22, 4 December 2008 (UTC)

Thanks for your comment. I understand what is the standard meaning of "partial" in mathematics. I have learned that in the discussion you referred to. But terminology evolves. For instance, in my native (mathematical) language a sphere is a solid object (such as a cube). However, in english a sphere seems to be defined as a surface (this means that the volume of any sphere is zero; this is confusing; according to my english textbooks, many native english engineers would disagree; in these textbooks, you can find formulas for computing volume and moment of inertia of spheres).

Also, in my native language a line can be either curved or straight, while in standard english line means straight line.

Moreover, an extremely large group of people all over the world (mostly in computer graphics) recently decided to call "homogeneous transformation matrix" the 4x4 matrix used to perform affine (non-homogeneous) transformations (e.g. roto-translation) on 3-D space. Unfortunately, this is now considered to be standard terminology in computer graphics.

Sometimes these changes/differences are useful or acceptable or consistent, other times (such as in the last example), they are inconsistent and terribly misleading. Some just accept standard terminology, but it is evident that some others do not, otherwise terminology would not change throughout the centuries. I just hope that those who have the courage and authority to advocate for a change will more frequently succeed when they are "right" than where they are not (indeed, in some cases they are not).

I am perfectly aware that Wikipedia cannot propose changes in terminology. The discussion on Talk:Partial function was an effort to make clear the rationale and advantages and drawbacks of standard terminology, by comparing it to other possible options. I concluded that standard terminology is not the best possible choice. You may agree or disagree, but this will not appear in the article. It will remain in the discussion section. It will make editors aware about the limits of standard terminology, and may convince some editor to add a sentence or two to explain the rationale (this is a difficult task, however, because I believe we proved that the rationale is not totally faultless). Paolo.dL (talk) 11:56, 4 December 2008 (UTC)

Very interesting and informative response! First, let me say that we agree on much. It was particularly intriguing to me (an amateur linguist) to hear about the extent to which some cognates between English and your native language (presumably l'Italiano?) are far from synonymous. Certainly as concerns sphere, when English-language mathematicians are speaking precisely, we universally interpret the word to refer to a two-dimensional surface, while the object corresponding to the sphere's interior is referred to as a ball. By comparison, although I don't know for sure the usage in French, the site http://www.le-dictionnaire.com provides two geometric senses of sphère, both "dans un espace à trois dimensions, ensemble des points situés à égale distance d'un point pris comme centre" and "solide décrit par la forme précédente". Anyway, most all of us anglophones take liberties and use the word sphere in many circumstances where the more rigorous would insist on using ball. Similarly, most English-language authors/speakers do generally consider curve to be a more general term than line, but certainly not all. And at least in non-technical contexts, nobody would assert that the term "straight line" was redundant.

As for homogeneous, I'm afraid I don't share your view that its use to describe certain transformation matrices (or coordinates) is inconsistent or terribly misleading, because homogeneous is used in many essentially unrelated ways in mathematics. As one example, in number theory the equivalence relation that partitions the integers according to their sets of distinct prime divisors is called homogeneity. For another example, an association scheme is called homogeneous if its 0th relation is equivalence. And even within ordinary differential equations the term homogeneous is used, according to context, to mean either of two quite different things. Just look at the article on homogeneity (mathematics) for further examples.—PaulTanenbaum (talk) 19:33, 5 December 2008 (UTC)

Thank you for the information you provided. I am aware of the distinction between ball and sphere and the analogous distinction between disk and circle. I can't understand why we need such a distinction for a circle and a sphere and not for a square and cube. I conclude that this is either an incomplete or an useless evolution of mathematical language in English (and notice that English textbooks in mechanical engineering do not endorse this distinction).

As for the use of the word "homogeneous", I agree that in different contexts it means different concepts, but when you use it in the context of transformations, homogeneous always refers to one of the conditions required to be linear (see linear transformation). By the way, even the redundant expression "homogeneous linear transformation" seems to be used according to some Wikipedia editor (I do not agree about redundant terminology: there's not such a thing as a non-homogeneous linear transformation!).

Now, a rototranslation (performed by a so-called "homogeneous transformation matrix") is not a linear transformation and does not meet the condition of homogeneity... There's another possible interpretation of the computer graphics terminology. In the intention of those who use the expression "homogeneous transformation matrix", homogeneous might refer to the matrix and not to the transformation. But homogeneous etimologically means: of the same (homo) kind (genus), or same gender. Well, do you know the structure of a 4x4 transformation matrix? It is made of vectors of different kinds. One of the row vectors is just [0, 0, 0, 1]. Three of the column vectors are unit vectors (with fourth element zero), the fourth (representing translation) is of course not necessarily a unit vector (and has a 1 rather than a 0 as fourth element). Would you call this structure "homogeneous"? I am sure you will agree that they call that transformation or matrix homogeneous just because the matrix contains homogeneous coordinates. Similarly, calling "Cartesian transformation matrix" a matrix containing Cartesian coordinates would be sloppy terminology. But at least it would not be conflicting with a different definition of the word "Cartesian" in the context of transformations! :-)

In sum,

1. the matrix elements are homogeneous coordinates (and that's correct terminology), but
2. the transformation is not homogeneous, and
3. the matrix is not homogeneous.

Paolo.dL (talk) 11:11, 6 December 2008 (UTC)

For a similar reason we should not say "3-D vector", but "vector in 3-D space" or "3-element vector". In other words, all vectors in Rⁿ are by definition 1-D arrays, so a vector in N-D space is not N-D. But when somebody writes or says "3-D vector" to mean "3-element vector", I am not so "disgusted" as when somebody writes "homogeneous transformation matrix" to say "matrix of homogeneous coordinates" or "affine transformation matrix", or whatever is the correct name of that matrix. Paolo.dL (talk) 11:22, 6 December 2008 (UTC)

Moving articles

Hi, and thank you for your contributions to Wikipedia. It appears that you recently tried to give Chord notation a different title by copying its content and pasting either the same content, or an edited version of it, into another page with a different name. This is known as a "cut and paste move", and it is undesirable because it splits the page history, which is needed for attribution and various other purposes. Instead, the software used by Wikipedia has a feature that allows pages to be moved to a new title together with their edit history.

In most cases, once your account is four days old and has ten edits, you should be able to move an article yourself using the "Move" tab at the top of the page. This both preserves the page history intact and automatically creates a redirect from the old title to the new. If you cannot perform a particular page move yourself this way (e.g. because a page already exists at the target title), please follow the instructions at requested moves to have it moved by someone else. Also, if there are any other pages that you moved by copying and pasting, even if it was a long time ago, please list them at Wikipedia:Cut and paste move repair holding pen. Thank you. VernoWhitney (talk) 12:27, 28 September 2010 (UTC)

Transcluded to Talk:Singular value decomposition

I've transcluded the A-class review discussion to Talk:Singular value decomposition. I've never done an A-class review before, but this is usually done for GA reviews because it makes the process more inclusive I think, and the review is more visible to regular editors. Sławomir Biały (talk) 18:16, 28 February 2011 (UTC)

Thank you

		The Modest Barnstar
		Thanks for your recent contributions! -129.49.72.78 (talk) 19:11, 29 April 2011 (UTC)

Carbohydrate

Please do not add or change content, as you did at Carbohydrate, without citing a reliable source. Please review the guidelines at Wikipedia:Citing sources and take this opportunity to add references to the article. This topic is within WikiProject Medicine and so requires high-quality systematic reviews for sources. Please read and follow the WP:MEDRS guidelines. Also applies to your edits on Dietary fiber. Zefr (talk) 15:03, 23 July 2018 (UTC)

Dietary fiber

Hi, your latest edit summary on Dietary fiber puzzles me. The article classifies resistant starch as insoluble fiber. And repeats twice, in the introduction, that resistant starch is fermented to produce short-chain fatty acids. Paolo.dL (talk) 20:34, 23 July 2018 (UTC)

Hello Paolo.dL. I felt your edit here did not improve the article lede, possibly confused it, and added either primary or out of date sources (see WP:MEDDATE and WP:MEDASSESS). The lede may need further clarification due mainly to the special case of resistant starch (RS-1,2,3) which 'resists' digestion in the small intestine, and may undergo digestion by colonic bacteria. This lede sentence: "Other types of insoluble fiber, notably resistant starch, are fermented to produce short-chain fatty acids" may be part of the confusion because resistant starch is actually 'fermentable' and so may be classified as partially soluble - rather than insoluble - fiber. I would suggest removing 'insoluble' from that sentence. This is perhaps the most recent review of resistant starch, and could be added to the article. We can discuss this further here on your Talk page, or move the discussion to the article Talk to engage others. --Zefr (talk) 14:48, 24 July 2018 (UTC)

Thanks for your explanation. I trust you about the fact that the reference (which I found on the article SCFA) is not reliable. Thank you for being selective, I appreciate it. It would be nice to say in the article about Dietary fiber that resistant starch is partially soluble. This means that there are three cathegories of dietary fibers (two of which may be grouped together). I mean that soluble and partially soluble may be considered to be in the same cathegory. We need to fix the table as well, however, to make the article consistent within itself. If you like, just do it. I see that you agree about article consistency, which was the reason why I edited. Paolo.dL (talk) 20:33, 24 July 2018 (UTC)

Thanks. Over the last decade, there have been conferences and professional associations that steered the definition from 'soluble/insoluble' to 'fermentable/non-fermentable'. Over the next day or two, I'll reread the major refs and offer a revision for the lede and table. There's also this review on RS, now suggesting a 5th type which should go in the article. --Zefr (talk) 21:40, 24 July 2018 (UTC)

This revision is a beginning to clarify a topic with subtypes of fiber having differing effects in the body. More editing is needed and I'll do more, but the challenge is to make the content understandable to the non-expert user, such as a high school student. --Zefr (talk) 16:45, 26 July 2018 (UTC)

Great job! Thank you again for sharing your knowledge with all Wikipedia readers, including me. Paolo.dL (talk) 20:53, 26 July 2018 (UTC)

There's something weird in the definition by the American Association of Cereal Chemists, as reported in the section Dietary fiber#Definition. It seems to esclude non-fermentable insoluble fiber (such as cellulose, as far as I know)... Paolo.dL (talk) 21:52, 26 July 2018 (UTC)

The AACC definition, published here in 2001, was the gold standard for the early years of this century, but it has not kept pace with the growth of science. The table should reflect the year of publication by the respective sources. That's why I feel the BNF document added today is a lay-friendly synthesis of what's relevant to date. --Zefr (talk) 22:34, 26 July 2018 (UTC)

Thank you again for the improvements. See my minor edit. Paolo.dL (talk) 20:45, 30 July 2018 (UTC)

Copying within Wikipedia requires attribution

Main page: Wikipedia:Copying within Wikipedia

Thank you for your contributions to Wikipedia. It appears that you copied or moved text from Trans fat into Butterfat. While you are welcome to re-use Wikipedia's content, here or elsewhere, Wikipedia's licensing does require that you provide attribution to the original contributor(s). When copying within Wikipedia, this is supplied at minimum in an edit summary at the page into which you've copied content, disclosing the copying and linking to the copied page, e.g., copied content from [[page name]]; see that page's history for attribution. It is good practice, especially if copying is extensive, to also place a properly formatted {{copied}} template on the talk pages of the source and destination. — Diannaa 🍁 (talk) 16:50, 24 August 2019 (UTC)