Talk:Sharaf al-Din al-Tusi

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Derivatives of cubic polynomials

I have removed the first sentence of the section Treatise on equations because it misrepresents the source cited. More details can be found on an archive of the Mathematics in medieval Islam talk page. An accurate account, written form a neutral point of view, of the various conjectures about how al-Din acquired his knowledge of the maxima of cubic polynomials should eventually be added to the article.
David Wilson (talk · cont) 14:00, 19 March 2011 (UTC)

COPYVIOs

I removed, piecewise, several WP:COPYVIOs from this article (from [1]) before deciding that it was pretty well all made of that stuff. So I took it all out.

Besides which, the polynomial / derivative stuff was wrong, per what is now in Mathematics in medieval Islam and the discussion there William M. Connolley (talk) 07:49, 27 April 2011 (UTC)

Derivatives of cubic polynomials again

I have now reverted this series of recent edits. Even though the last of these seems like a reasonable paraphrase of the source cited, the language used by this tertiary source is unfortunately itself quite likely to be misunderstood, unless it is read in conjunction with some of the more scholarly literature on the subject. If you consult that literature—some of which is cited by the source—you will find that al-Ṭūsī left no clue as to how he found out that the maximum of the function b x − x³ occurs when x = √(b/3). It's certainly plausible that he might have discovered this fact by some process similar to taking a derivative and setting it equal to zero, and some scholars have argued that he must have done so. But, as others, notably J.P. Hogendijk and J.L. Berggren, have pointed out, there are other ways that he could have discovered this fact without having had to use the derivative at all. Thus, for Wikipedia to state as undisputed fact that al-Ṭūsī discovered some sort of derivative, even implicitly, would be a blatant violation of its policy on maintaining a neutral point of view. All of this has already been discussed extensively here and here.
David Wilson (talk · cont) 10:06, 19 February 2017 (UTC)

I agree with the above. My edit was intended to bring the paragraph in line with the source, but I wasn't that happy with the source's phrasing in this instance. So I don't mind the removal of my edit, but I do think that something needs to be said about al-Ṭūsī's mathematical contributions. Perhaps a copy of what you included in the Differential calculus page. My general feeling is that a controversy needs to be discussed and not hidden. If we don't include something, I fear that we shall be dealing with this POV pushing for a long time. --Bill Cherowitzo (talk) 18:52, 19 February 2017 (UTC)

I agree with Wcherowi, something must be said about that in the article, that's why i added a line about his supposed implicit use of a derivative and i made sure to show the two points of view (Rashed and Hogendijk).— Preceding unsigned comment added by Wikaviani (talk • contribs) 00:31, September 4, 2017 (UTC)

And again

The disputed claim that al-Dīn_al-Ṭūsī discovered the derivative of cubic polynomials has just been re-added to the article by this edit, with a citation to a source which is undoubtedly reliable, but which does not support the claim. I shall therefore be reverting the edit. I refer the editor who made it to one of Wikipedia's guidelines which says you should only cite a source directly if you have read that source yourself. An account of what the cited source actually does say can be found here.
David Wilson (talk · cont) 00:28, 11 June 2017 (UTC)

Edit warring and removal of sourced materials

I reverted edits by user Wcherowi as his edits where unsourced and look like edit warring with anonymous user 37.172.49.217. University of St Andrews is a reliable source and R. Rashed is also a reliable source about this topic and these two sources are cited in many good articles on Wikipedia. Please user Wcherowl, if you have different reliables sources claming something else, bring them on the talk page and do not remove sourced informations. — Preceding unsigned comment added by 2a01:e34:ee9d:a200:f039:9ff8:3983:5318 (talk) 11:57, September 3, 2017‎ (UTC)

The two sources cited in the edits by the anonymous user from IP 37.172.49.217 were the University of St Andrews's MacTutor website, and an article, Innovation and Tradition in Sharaf al-Dīn al-Ṭūsī's Muʿādalāt, by J.L. Berggren in the Journal of the American Oriental Society. However, some key claims made in the material added by these edits are egregious misrepresentations of these sources, and simply not supported by either of them. To wit:

• "He also developed the concepts of a derivative function … ". This is cited to the Mactutor article, but nothing remotely like that is stated anywhere in that article. What it actually says is:

"Basically using the derivative of this expression, al-Tusi finds [where] the maximum occurs …

"Of course al-Tusi's use of the derivative of a function, without of course saying so, is very interesting. The paper [11] attempts to discover the origin of this implicit use of the derivative, which the author claims arises from algebraic proofs based on analytical procedures. The paper [12] suggests that a rather different approach, not one analogous to the modern derivative, lay behind Al-Tusi's method. The papers [10] and [14] contribute to this discussion; see also [2], [3] and [4] for further insights.

Moreover, Berggren's article actually contradicts the notion that even an implicit use of derivatives in al-Tusi's work can be considered an established fact.

• "He understood the importance of the discriminant of the cubic equation to find algebraic solutions to certain types of cubic equations." This is cited to Berggren's article, which nowhere uses the term "discriminant" for any purpose, let alone as the name of something which al-Tusi supposedly recognised the "importance" of. The Mactutor article does use the term "discriminant" once:

"Then Al-Tusi deduces that the equation has a positive root if

D = b³/27 - a²/4 ≥ 0

where D is the discriminant of the equation."

but nowhere says anything about al-Tusi "understanding" its "importance". In fact, the statement in the MacTutor article is a little misleading, in that al-Tusi never expressed inequalities in forms like A – B ≥ 0. Since he didn't recognise that an expression of the form A – B made any sense if A < B, he never rewrites inequalities such as A ≥ B or A ≤ B in the forms A – B ≥ 0 and A – B ≤ 0 which we recognise today as being equivalent.

Your reversions of user Wcherowi's edits were therefore completely unwarranted.

David Wilson (talk · cont) 08:46, 4 September 2017 (UTC)

Hi, In the source it's stated that Roshdi Rashed (who is a reliable source on that topic) writes that Al-Tusi is the founder of algebraic geometry (..."represents an essential contribution to another algebra which aimed to study curves by means of equations, thus inaugurating the beginning of algebraic geometry"). this has been removed from the article and i would likely ke to know why. If no legit explanation is provided, i will edit again the article with this statement. More, users Wcherowi and Wikaviani edited the article by saying that the implicit use off a derivative of cubic function was claimed by Rashed but challenged by Hogendijk and Berggren, and this has been removed to although being true... an explanation eoylb br welcomed...

Your comments are a little out of date. The article has been changed (before you wrote this, but maybe a tie time-wise) in what I think is a positive way. Wikaviani and my edits have never been removed from the article, but there is some difficulty with looking at earlier versions of the page at the moment (I hope that this gets fixed). --Bill Cherowitzo (talk) 22:30, 5 September 2017 (UTC)

I'd say mentioning algebraic geometry is justified, but I'm not sure about "founder of". Perhaps this quote might be useful. Wiqi⁽⁵⁵⁾ 22:44, 5 September 2017 (UTC)

I changed the phrase with algebraic geometry to one closer to the source. But i think that the statement "He is credited as having turned trigonometry from a tool used in astronomy into a mathematical subject in its own right" is wrong as the one who performed this change was NASIR al din al Tusi and not SHARAF al din al Tusi. I looked at the source cited and there nothing about Sharaf's work in the field of trigonometry... if there is a concensus about this point, i will remove that sentence.

If it is the wrong al-Tusi then by all means remove the sentence. I reverted your change for two reasons. First of all the St. Andrews citation is not an independent source since all they are doing is citing Rashed's comment. That article had already been cited three times and there was no need for a fourth reference to it. Rashed's comment seems to me to be a bit of hype (or perhaps just how others are using his comments) and I would like to see some independent source also make this claim before reinstating it. --Bill Cherowitzo (talk) 01:49, 6 September 2017 (UTC)

For anonymous user who opened this topic about "edit waring": there is nothing such that here, we're just discussing some issues in the article to make it the more accurate possible. I agree with user wcherowi when he says that we should remove Tusi's supposed work in trigonometry as it does not appear in the source cited. But i do not understand why we should change Rashed's sentence about Tusi as the beginner of algebraic geometry and write instead "lefts his mark". I think that if we cite a source, we should remain as close as possible to it and not change it arbitrarily.--Wikaviani (talk)

I don't want to be engaged in an edit waring, but i changed again the phrase about algebraic geometry. If we cite Rashed, let's cite him properly... — Preceding unsigned comment added by 2A01:E34:EE9D:A200:C4AC:5CC0:900A:7C11 (talk) 21:33, 6 September 2017 (UTC)

Discriminant

The current reference cited in the article as justification for the statement "He understood the importance of the discriminant of the cubic equation to find algebraic solutions to certain types of cubic equations"—namely J.L. Berggren's article Innovation and Tradition in Sharaf al-Dīn al-Ṭūsī's Muʿādalāt—does not support it. Berggren's article contains not a single mention of the term "discriminant", and as far as I can see there is nothing whatever in the article to indicate that Berggren would agree with the statement. Unless someone can supply a decent source to justify the statement within a few days, I shall remove it from the article.
David Wilson (talk · cont) 16:17, 15 September 2017 (UTC)

I have managed to track down a statement by Roshdi Rashed which can be used to justify including in the article at least an attribution to Rashed of a statement to the effect that al-Tusi "understood the importance of the discriminant" of cubic polynomials. In my opinion, however, this attribution needs to be qualified by stating certain facts about al-Tusi's treatment of cubic equations which might be regarded as casting some doubt on the accuracy of Rashed's statement.

David Wilson (talk · cont) 18:04, 16 September 2017 (UTC)

Citation check needed

One of the sources currently cited in the lead as support for the statement that al-Tusi was Persian is page 247 of the 2008 second edition of Helaine Selin's Encyclopaedia of the History of Science, Technology, and Medicine in Non-Western Cultures The only searchable edition of that encyclopaedia available in Google Books appears to be the 1997 first edition, whose page 247 contains nothing whatever about al-Tusi. Jan Hogendijk's article on al-Tusi on p.894 of the same edition merely says that he was born "Tus (Iran)", which is far from ideal as a citation to justify the statement that he was Persian.

The Minor planet center web page cited at the end of the lead is also very far from ideal, in my opinion. Although it does say specifically that al-Tusi was Persian, and is published under the auspices of the prestigious Harvard-Smithsonian Center for Astrophysics, it is nevertheless a page about astronomy, not the history of mathematics, and I don't believe it's author's opinions on the latter subject should be assumed any more authoritative or reliable than that of any other well-educated layman.

Since I have convenient access to a printed copy of the cited 2008 edition of Selin's encyclopaedia in a local University library, I will check it later today.
David Wilson (talk · cont) 16:21, 18 September 2017 (UTC)

I have now checked the source, which says "This [i.e. the linear astrolabe] was invented by Iranian mathematician Sharaf al Dīn al-Tūsī … ". The article, Astrolabe, in which the text appears, seems to be a verbatim copy of the same article which appears on pp.74–75 of the 1997 edition of the encyclopaedia.

Since I've no idea whether the terms "Persian"and "Iranian" can be considered completely synonymous or not, I have replaced the former with the latter in the article.

David Wilson (talk · cont) 04:59, 19 September 2017 (UTC)

According to our article Iran the terms are interchangeable especially in cultural contexts. Iranians have always used Iran and there was a movement at one time to have everyone drop Persia in favor of Iran, but this has not prevailed. My preference would be for Persian since that conveys (for me, and I now realize that this is mistaken) a more historical flavor. --Bill Cherowitzo (talk) 05:28, 19 September 2017 (UTC)

I have no preference one way or the other between "Iranian" or "Persian", as long as a good source can be found to support the choice. I am, however, fairly strict in what I consider a "good" source. I had earlier found some books in Google Books which described Sharaf al-Din al-Tusi as "Persian", but for various reasons I didn't find any of them satisfactory. However, I've now found this source, which seems to me to be impeccable, and describes our al-Tusi as a "Persian astrolabe maker". So I would be perfectly happy for this source to be added to the references and cited as justification for changing the description back to "Persian".

David Wilson (talk · cont) 07:48, 19 September 2017 (UTC)

Quality of sources

There is a dispute concerning the following sentence and its citations. Some editors have insisted on

Sharaf al-din al-Tusi has been described as the beginner of algebraic geometry.

while several other editors (myself included) prefer

According to Rashed he was also responsible, along with al-Khayyam, for "laying the foundations of algebraic geometry".

References

There are two issues that I have seen. The first deals with the quality of the references given in the first version. The three citations given are all tertiary sources (note that I am not saying that they are unreliable, only that they are not secondary sources). The St. Andrews site supports the claim because it quotes Rashed. The second citation is to a generic work on religion and science and gives no reference for its statement. The third citation uses encyclopedias as its sources. Of these three, the St. Andrews site is the best, but again it is not a secondary source. The second version directly cites Rashed's book, and since he is a historian this is a secondary source. The wording of the second version is precisely what can be found in Rashed's book and this can be verified by the citation links. The second issue appears to be an objection to referring this opinion to Rashed, with the claim that others believe it also. While this may certainly be true, that doesn't mean that the second version is false or misleading. Also, I have seen no evidence that this statement has any sources other than those that can be traced back to Rashed. If a reliable secondary source can be found that is independent of Rashed, then there will be grounds for removing the reference to him, but so far this is not the case.--Bill Cherowitzo (talk) 21:56, 6 October 2017 (UTC)

When following the link OIS, there is a sign in page, this is why i looked for the real article from John L. Esposito, chief editor of that source.

Here is a link pointing to his book "The Oxford History of Islam" :

https://books.google.fr/books?id=9HUDXkJIE3EC&pg=PA188&lpg=PA188&dq=Al-Tusi+introduced+a+new+discipline%E2%80%94algebraic+geometry%E2%80%94that+relies+on+equations+to+study+curves.%22&source=bl&ots=XPTsT1hkMh&sig=DC59ymcLgnfr1Nx42RkM5MLlq1U&hl=fr&sa=X&ved=0ahUKEwiSrtiBl93WAhVJIcAKHSDnAxQQ6AEIUDAF#v=onepage&q=Al-Tusi%20introduced%20a%20new%20discipline%E2%80%94algebraic%20geometry%E2%80%94that%20relies%20on%20equations%20to%20study%20curves.%22&f=true

This source, published by OUP, states (page 187) :

"In its analyltic approach, Al-Tusi's work on equations marks the beginning of the discipline of algebraic geometry: the study of curves by means of equations"

This is a reliable secondary source because it's Esposito's opinion...

More, when having a look at the authors, there is nowhere the name of Rashed.

Here are conditions for a good source on Wikipedia:

  * The piece of work itself (the article, book)
   *The creator of the work (the writer, journalist)
   *The publisher of the work (for example, Random House or Cambridge University Press)

Which one of these conditions is broken when saying "Al Tusi has been described as the beginner of algebraic geometry" and citing the sources proposed above ?

With your proposal: "According to Rashed he was also responsible, along with al-Khayyam, for "laying the foundations of algebraic geometry", we cite only Rashed's opinion and we have no idea what other scholars think about that...Wikaviani (talk) 00:49, 7 October 2017 (UTC)

So who is Esposito? What are his qualifications that make him an expert on this matter? As for the Oxford History of Islam, that is not a secondary source. You can tell this because no primary sources (or any other sources) are cited in the text you have linked. You can not tell if he is channeling Rashed (or anyone else) because he does not say where he is getting his information from. This book is a popularization and not a scholarly work. There are other experts in ancient Islamic mathematics and if you can find a statement from one of them that agrees with Rashed's opinion your argument would have a leg to stand on.--Bill Cherowitzo (talk) 05:02, 7 October 2017 (UTC)

On your talk page, you told me : "Please read my comments more carefully. The version I would like to see is directly sourced to Rashed, so how can you claim that I have indicated that he is not a reliable source?" You said that about this topic on algebraic geometry...

That's what i did, i read your comments carefully and in your contributions, i found that comment from you, september 3, 2017:

"Reverted 3 edits by 37.172.49.217 (talk): Although cited to St. Andrews, the quote is due to R. Rashed whose bias in this matter is well known" You were speaking about a contribution of an IP user citing St Andrews and RASHED about the field of...algebraic geometry !

Now you want to keep Rashed as a reliable source and say that Oxford history of islam is not a reliable source...

On your page it's said you're a mathematician, i thought than mathematicians were logical guys... So i'm just going to revert your edit again, and consider this case as closed. Thanks for your "contribution". Farawahar (talk) 11:26, 7 October 2017 (UTC)

Once again you seem to be very selective about what you read and what you choose to ignore. On my talk page I explicitly pointed out that I don't agree with Rashed, but my disagreement doesn't matter. There is no doubt that Rashed made the statement and I support the version that says that he made that statement. This does not mean that I endorse his point of view. If I were to act in any other way I would be trying to impose my own POV on the article, in much the same way you are trying to impose yours. The edit summary that you found concerned an earlier version of this statement which did not mention Rashed and I reverted it on exactly the same grounds that I have reverted your use of the St. Andrews site for this purpose, although I was a bit more explicit about my opinion of Rashed's POV. Also, I have no where claimed that the Oxford History of Islam is not reliable, my claim was that it was not a secondary source and I explicitly pointed that out above. The Rashed citation is a perfectly reliable primary source for the statement that "he made this statement" (one of the few instances when primary sources are allowable) and is a secondary source for the statement itself. I am happy that you reviewed my editing history, I have nothing to hide there, but the conclusions you have reached seem to be more of a reflection of your biases than of mine. --Bill Cherowitzo (talk) 17:40, 7 October 2017 (UTC)

As to Wikaviani's most recent additions. The first is an unpublished paper and so, considered unreliable by Wikipedia standards and the second is an encyclopedia entry that does not in fact support the statement. I would suggest that you try to post any new citations here on the talk page so that they can be discussed rather than constantly reverting the article. --Bill Cherowitzo (talk) 18:04, 7 October 2017 (UTC)

So, if i understand well, When you say above "This book is a popularization and not a scholarly work", you don't say that this source is not reliable ? The point is that you reverted an IP who used a perfectly reliable source just because you do not endorse Rashed's POV, excuse me to say so but nobody cares about your opinion on Rashed... Later, you blatantly changed your opinion like that arranges you and you dare saying that I try to impose my POV ??? From which planet do you and your vandal friend William M Connolley (who revert as he breaths without providing any legit explanation...) come from ? Sorry, you should try to find a better explanation and if you can't, i'll revert your edit again... Farawahar (talk) 19:24, 7 October 2017 (UTC)

(edit conflict) There are a couple of serious problems with your proposed text, "Sharaf al-din al-Tusi has been described as the beginner of algebraic geometry." First, "beginner" is certainly the wrong word to use for someone who has been described as "the inaugurator" of anything, since the former word means "a person just starting to learn a skill or take part in an activity"—to quote the Oxford Dictionary of English—and not  "the first person to acquire the skill or undertake the activity concerned." Also, the normally correct English idiom for "a beginner in X" is just that, not "the beginner of X", which will immediately be recognised by any well-educated native speaker of English as having probably been produced by a non-native speaker of the language. To be sure, the native English speaker will recognise that "the beginner of algebraic geometry" is proably not intended to mean "a beginner in algebraic geometry", but rather something like "the (or possibly "a") founder of algebraic geometry", which brings me to the second—and more serious—problem with the text.

If Hogendijk's description, in his article Sharaf al-Dīn al-Ṭūsī on the Number of Positive Roots of Cubic Equation, of the contents of al-Tusi's treatise on algebra is accurate and comprehensive—which I have no reason to doubt—, then there is nothing in that treatise which could reasonably be described as being algebraic geometry proper. It is therefore absurd to describe al-Tusi as "a founder of algebraic geometry", and nowhere, as far as I'm aware, does Rashed or any other credible authority say or imply that he was such a founder.

What Rashed writes, in the passage allegedly supporting the text you want to add to the article, is:

Indeed, it [i.e. "al-Tusi's work"] represents an essential contribution to another algebra which aimed to study curves by means of equations, thus inaugurating the beginning of algebraic geometry." (emphasis added)

Note that the final phrase is "the beginning of algebraic geometry", not "algebraic geometry". If Rashed had meant to say "thus inaugurating algebraic geometry", presumably that's what he would have written. Thus, by ignoring this crucial distinction, the text you want to add to the article actually misrepresents what Rashed has written.

To clarify this, algebraic geometry most certainly is not "the study of curves by means of equations", as two of your sources have mischaracterised it. While the study of curves by means of equations is one essential ingredient of algebraic geometry it is not the only one, and does not, by itself, constitute doing algebraic geometry. One other ingredient, for instance,—also essential—is the idea of representating a point on a curve by a set of coordinates. No-one, including Roshdi Rashed, as far as I'm aware, has suggested that this idea had occurred to anyone before René Descartes in the 17th century. It was therefore unknown to any mathematicians of the 12th and 13th centuries, none of whom can therefore be reasonably described as having practised algebraic geometry in any way.

A few more periphal points:

• The article in the Oxford History of Islam was not written by John Esposito, who is the editor of the book (and the author only of its final chapter, the 15th). Your quotation comes from Chapter 4, Science, Medicine, and Technology, The Making of a Scientific Culture, written by Ahmad Dallal.
• While Dallal certainly appears to be a reputable authority on the history of Islamic science, he is obviously not a mathematician, and his blunder in characterising algebraic geometry as "the study of curves by means of equations" demonstrates unequivocally that, on that subject at least, he doesn't know what he's talking about. To be fair to Dallal, it's easy to see how anyone reading the statement of Rashed's quoted above might get the mistaken impression that that's what algebraic geometry is.
• Concerning this source, you write above "More, when having a look at the authors, there is nowhere the name of Rashed." Please take a look at the bibliography for Chapter 4, where you will find the following text:

"In the past two decades Roshdi Rashed has been instrumental in advancing scholars' understanding of the various disciplines of Arabic mathematics. Rashed has produced several ctitical editions, translations and commentaries on Arabic mathematical texts in the disciplines of algebra, geometry, arithmetic, numerical analysis, infinitesimal mathematics, and mathematical optics. An overview of some of his findings is available in Roshdi Rashed, The Development of Mathematics: Between Arithmetic and Algebra, trans. A.W.F. Armstrong, Boston Studies in the Philosophy of Science no.156 (Dordsdrecht, Boston, London: Kluwer Academic publishers, 1994)."

In view of this, it seems pretty clear to me that in the quotation you have given from the Oxford History of Islam, Dallal is not giving an opinion on which is independent of Rashed's. On the contrary, it seems pretty obvious that he's relying directly on Rashed's work, and has simply misread it.

David Wilson (talk · cont)

Ok guys (and ladies) let's calm down and try to solve this issue. As far as i know, the use of a secondary source on Wikipedia is preferable but not obligatory. Wicherowi said himself that the sources cited by Farawahar are reliable, so i think that as long as Wicherowi does not provide a cite that contradicts these sources, Farawahar's edit is legit and should not be reverted. we do not need consensus here because Wicherowi and William M Connolley did not produce sources contradicting Farawahar's ones. Wicherowi, i'm sorry to tell you that, but you can not tell everything and its opposite. For my part, i admit a mistake when choosing the last two sources and i'm ok to remove them. If it's impossible to fix this by ourselves, i'll ask for a dispute resolution. Wikaviani (talk) 00:45, 8 October 2017 (UTC)

I do wish you boys would stop trying to put words in my mouth, everything that I have said is in print and can be verified by anyone. I never said that these references were reliable; what I did say was that I didn't call them unreliable. I have no idea of how reliable they are and I have kept any doubts to myself. What I do know is that they are not secondary sources. As to the use of secondary sources on Wikipedia, the policy statement is Wikipedia:ANALYSIS and it reads:

Policy: Wikipedia articles usually rely on material from reliable secondary sources. Articles may make an analytic, evaluative, interpretive, or synthetic claim only if that has been published by a reliable secondary source.

And to be clear about it, calling al-Tusi the "beginner of algebraic geometry" is an interpretive claim. If you wish to invoke any form of dispute resolution I will be more than happy to oblige.--Bill Cherowitzo (talk) 05:28, 8 October 2017 (UTC)

Wicherowi, i was talking about your opinion on Rashed which seems to have changed, not your statement about the sources...

David J Wilson, first of all i agree with you when you speak about the word "beginner" which is a bad choice here, let's find another one. But i don't agree on the other points :

First, Dallal is effectively the author of the chapter four, but he does not speak only about Rashed, but also Saliba and Morélon. He does not say these guys were his sources, this is your interpretation, and even if so, this would mean that his statement is sourced by three scholars and not only Rashed. More, O'Connor and Robertson of St Andrews are not only citing Rashed, they also agree with him: "What is in this Treatise on equations by al-Tusi? Basically it is a treatise on cubic equations, but it does not follow the general development that came through al-Karaji's school of algebra. Rather, AS Rashed writes:-... it represents an essential contribution to another algebra which aimed to study curves by means of equations, thus inaugurating the beginning of algebraic geometry." You say Dallal is not a mathematician, but Robertson and O'Connor are prominent mathematicians, do you think they misread Rashed too ???

Second point, it seems that you confuse algebraic geometry and analytic geometry... Even if there is no consensus on that point (see https://books.google.fr/books?id=GzjpCAAAQBAJ&pg=PA887&lpg=PA887&dq=helaine+selin+sharaf+al+din+al+tusi+algebraic+geometry&source=bl&ots=nHVPBprJ0D&sig=NLH1QvmIhaBikdk1DPxOAFpeUUc&hl=fr&sa=X&ved=0ahUKEwjq2MjE9uDWAhXQa1AKHXBeDA0Q6AEIWDAL#v=onepage&q=helaine%20selin%20sharaf%20al%20din%20al%20tusi%20algebraic%20geometry&f=true page 887), Descartes is considered by many the founder of the latter, not the first...

Third point, you say : "While the study of curves by means of equations is one essential ingredient of algebraic geometry it is not the only one, and does not, by itself, constitute doing algebraic geometry." We're not saying that Tusi inaugurated all the branches of algebraic geometry, but of course only the elementary part of it and the study of curves by the mean of equations is a part of this field (see above the statement of O'Connor and Robertson...) Your statement is like saying that Euclid can not be considered the father of geometry because he did not contribute to non-Eucilidian geometry !

According to me, your position is weak, as none of you provides any source for his claims other than his own opinions and interpretations (Hogendijk does not contradict the sources above)... Wikaviani (talk) 11:40, 8 October 2017 (UTC)

I agree with the statements above. As you suggest, i'm going to make a statement which is closer to the source cited. Farawahar (talk) 15:01, 8 October 2017 (UTC)

Wikaviani stated

"Wicherowi, i was talking about your opinion on Rashed which seems to have changed, not your statement about the sources..."

in the message following the one in which he says

"Wicherowi said himself that the sources cited by Farawahar are reliable, ..."

which I objected to. I am finding it hard to keep track of any argument with all this cherry-picking, not only of mine but now also your own statements. As to my opinion on Rashed, that has never changed, I do not agree with him and consider him to be biased in this matter. I could go on, at length, as to why I think that but I won't, since my opinion is not germane to this discussion. What you seem to interpret as my changing opinion is the fact that I can put aside my personal viewpoint and try to be as objective as I can with respect to evaluating the quality of the sources. This is what is expected of any editor in order to maintain a WP:NPOV, and I am sorry that you do not understand that point. Also, your statement

"More, O'Connor and Robertson of St Andrews are not only citing Rashed, they also agree with him:"

is very naive. Are you really trying to claim that they agree with everything on their website? That is tantamount to calling them biased in their relating of the history of mathematics ... only posting things with which they personally agree. That is quite an insulting thing to say about historians who are trying to provide a high quality service to the community. --Bill Cherowitzo (talk) 18:46, 8 October 2017 (UTC)

Wicherowi, you say:

" What you seem to interpret as my changing opinion is the fact that I can put aside my personal viewpoint and try to be as objective as I can with respect to evaluating the quality of the sources"

Reverting an user who used Rashed as source shows that your statement is nothing but a lie... Anyway, i'm not here to teach you honesty.

You said above :"I do wish you boys would stop trying to put words in my mouth, everything that I have said is in print and can be verified by anyone". You should apply this to yourself. Since "everything that I have said is in print and can be verified by anyone", could you please tell me where i said that Robertson and O'Connor "agree with EVERYTHING on their website" ? I just said that the sentence quoted in the article and that comes from their website means that they agree with Rashed on this point. You should avoid caricature other users...

And now, i think we're done here. Wikaviani (talk) 20:26, 8 October 2017 (UTC)

Truth does seem to be a flexible commodity in your hands.

"Reverting an user who used Rashed as source shows that your statement is nothing but a lie..."

I have never reverted a user who used Rashed as a source. I reverted a user who used the St. Andrews site (the same as is currently being used) without mentioning that the statement was from Rashed.

"could you please tell me where i said that Robertson and O'Connor "agree with EVERYTHING on their website" ?"

I didn't say that you said that, I asked (did you see the question mark?) if you were claiming that. But in point of fact you have provided the answer to your own question in the very next sentence:

"...the sentence quoted in the article and that comes from their website means that they agree..."

Doesn't this say that they agree with every sentence quoted on their website? So if they quote opposing points of view does that mean that they agree with both? This is pretty silly.--Bill Cherowitzo (talk) 21:11, 8 October 2017 (UTC)

I don't follow your argument here. Although I'm completely baffled by a lot of what Wikiaviani has written, I presume he is here simply referring to the sentence of O'Connor and Robertson's which begins "Rather, as Rashed writes : .. ", and I take his argument to be nothing more than that this sentence constitutes an expression of agreement with the statement of Rashed's which they subsequently quote. It seems like a perfectly reasonable argument to me.

David Wilson (talk · cont) 00:54, 9 October 2017 (UTC)

• Comment: We actually have an essay (though not a policy) that gives some advice: "Stacking" tertiary source citations after a sufficient secondary one is not advised; it does not add more verifiability to the claim in the article, it simply adds clutter.. In this case, Rashed is a sufficient secondary source. He is a well-known authority on the subject, even contributed the "Mathematics" article in the widely cited EI2 (vol.8, p.549). Trying to cast him off as a translator or insisting on using an attributive statement -- without a source contesting his claims -- doesn't strike me as neutral. How about just having a short passive sentence: "Sharaf al-Din al-Tusi's "Treatise on equations" has been described as inaugurating the beginning of algebraic geometry.[cite Rashed]." Wiqi⁽⁵⁵⁾ 23:35, 8 October 2017 (UTC)

With the exception of the sentence "Trying to ... strike me as neutral"—on which I'm not prepared to offer an opinion—I fully agree with this. While O'Connor and Robertson quote Rashed's statement, and apparently agree with it, the statement itself is Rashed's alone, and would be best cited directly to the source where he makes it. Not doing so when the source is readily available online is very poor scholarly practice, in my opinion.

David Wilson (talk · cont) 00:54, 9 October 2017 (UTC)

Although he speaks english fluently, Wicherowi claims not to understand the words "RATHER AS"...and says "Truth does seem to be a flexible commodity in your hands" and other nonsenses to me instead of applying these "advices" to himself, showing, AGAIN, his obvious lack of honesty, this is why, as i said above, i'm done with him here.

David J Wilson, first of all, I'm truly sorry that my words baffled you and since you seem to be someone honest, i agree to clarify any of them on your demand.

As you said above, Robertson and O'Connor agree with Rashed and since they are mathematicians and historians of mathematics, their opinion on this topic matters :

Edmund Frederick Robertson :

https://risweb.st-andrews.ac.uk/portal/en/persons/edmund-frederick-robertson(feaf9833-94d6-45e5-9089-26a5a2f16447).html)

Research overview:

algorithm design; algorithm implementation; computational group; computing; coset enumeration; finite simple group; group presentation; group theory; permutation; semigroup; monoid; history of mathematics

Thanks for your contribution

When looking at the history of editing of the article, a version close to Wiki55's one has been edited by Farawahar (but he cited St Andrews and not Rashed...) and, of course, changed by Wicherowi... Your proposal is okay for me, we should state what Wiqi55 proposes and cite Rashed. Wikaviani (talk) 10:22, 9 October 2017 (UTC)

It's done, but i took this reference in an old edit of the article, so, it's possible that i made a mistake. someone should check that (i don't have Rashed's book to do so). Wikaviani (talk) 08:07, 9 October 2017 (UTC)

Actually, there was a link in the source leading to his book (totally or partly...), but the pages cited do not support the claim, we should find the right pages or, if not available, return to a cite from St Andrews. — Preceding unsigned comment added by Wikaviani (talk • contribs) 12:45, 9 October 2017 (UTC)

It's on p.103, but you need to start reading on page 102 to get the context. I have now added the page numbers to the citation, and a link directly to p.102 of the online copy of the book.

David Wilson (talk · cont) 12:54, 9 October 2017 (UTC)

Ok, thanks. I would like to ask you a question, which of my words baffled you and why ? This is important for me to know this, because i try to be as respectful as i can. (in fact, I do not know if you meant that my words hurt you or if you said that because you consider what i said was so false that it shocked you...). Thanks. Wikaviani (talk) 13:34, 9 October 2017 (UTC)

No, I was not hurt or shocked, and I did not think you were being disrespectful. I merely think that you may have badly misunderstood some of the things I wrote in the comments of mine that you were replying to (though I do try to keep in mind the possibility that my bafflement could well be the result of a misunderstanding on my part, rather than yours). I had actually prepared a long post which listed some of the statements of yours that I found most baffling and tried to explain in some detail (probably more excruciating than necessary) why I found them baffling. However, just as I was putting the finishing touches on the comments, I saw that editor Farawah was willing to settle for a version of the disputed text that I found completely unobjectionable. Since I then no longer considered it of any great importance for the misunderstandings to be cleared up, I decided that posting my comments would just add unnecessary clutter to the talk page, and I discarded them. Since you say it is important for you to know which of your statements I found baffling, I will try to identify them on your talk page as I find the time to do so.

David Wilson (talk · cont) 17:32, 9 October 2017 (UTC)

Thank you very much for your answer. Wikaviani (talk) 22:15, 9 October 2017 (UTC)