I'm thinking (1) because searching "curve γ" on Google Books turns up various examples where γ or Γ is used when a second curve needs to be named in addition to one called C.
www.google.nl/books/editio...
www.google.nl/books/editio...
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Via ScienceDirect / Historia Mathematica :
1) A Euclidean proof for the Fourth Postulate : buff.ly/1anVGQd
2) There is no Euclidean proof of the fourth postulate : buff.ly/AeXC5T5
3) There is no obstruction to a Euclidean proof for the fourth postulate : buff.ly/EK6rk5K
#mathematics #math #maths
Poster for the spring school, with some details. Participants will learn (1.) how to use a standard astrolabe, (2.) hos to read most of the inscriptions, (3.) history of astrolabes in the Arabic-Islamic tradition, (4.) identifying fake astrolabes, and more.
One-page information sheet repeating some of the information on the poster, but with a few more details about applying.
Call for applications, free school on Arabic-Islamic Astrolabes at the Institute for the History of Arabic-Islamic Sciences in Frankfurt; March 23 workshop for experts, March 24-26 classes for advanced students. Classes in English, details below; apply by January 15th, 2026. #HistSTM #MedievalSky
Fact-checking Netz's mischaracterisations of Kuhn and Koyré: intellectualmathematics.com/blog/netzs-f...
Drawing a circle with a rope. digi.vatlib.it/view/MSS_Vat...
Much of Euclid’s Elements is easily misunderstood. Some proofs seem to have logical gaps. Some constructions seem pointless, others seem needlessly convoluted.
Each of these provides a window into how the ancient Greeks thought about math and the philosophical role that geometry played.
the Notices of the DEI
I believe the Greek says straight lines (εὐθεῖας γραμμὰς) just as in the Elements. "Rays" seems to be an erroneous and misleading translation.
Euclid says correctly: If one draws such lines, this is how they behave. For example when doing problems like this: datagenetics.com/blog/decembe... Everything about this perfectly fits Euclid's text.
A true statement about how lines emanating from a point behave. It does not say that that is how human vision actually operates physically. We use the same principle today when doing geometrical optics: connect the eye to points of interest by lines, then investigate the angles between them etc.
Nothing in Euclid says that he was committed to an extramission theory of sight. He describes visual phenomena relative to an observer, but this could just as well be understood the same way as when a heliocentric astronomer uses a geocentric framing or terminology for practical purposes.
In my geometry course I made a slide on this inspired by your book. intellectualmathematics.com/geometry/
Not sure, maybe eventually but I have other things planned there to appear soon.
My new article, on why Euclid had to postulate that all right angles are equal: www.sciencedirect.com/science/arti...
There is hardly anything substantial as far as I know, except old things in Italian. On a later part of the abacus school tradition I enjoyed the chapter zbmath.org/7940758 and hope to read the book link.springer.com/book/10.1007....
Viktor Blåsjö's review of the book "Form & Number: A History of Mathematical Beauty" by Alan J. Cain, is now live at tug.org/books/review...
My obituary of Henk Bos, who opened the eyes of so many of us to the history of mathematics: research-portal.uu.nl/ws/portalfil...
But how are you supposed to “draw the tangent line”? Archimedes doesn’t say. Does he think that drawing tangents is somehow “more given” or more basic than rectifying a circle (i.e., knowing π)? Unclear why one would think that.
I believe Aristarchus did not make a "lousy measurement" (15:58). Rather, he deliberately underestimated the size of the sun, and showed that even in this worst-case scenario it is way bigger than the earth (i.e. heliocentrism wins). See arxiv.org/abs/2102.06595 §7.6.
Torricelli's trumpet is not counterintuitive Opinionated History of Mathematics > • Play There is nothing counterintuitive about an infinite shape with finite volume, contrary to the common propaganda version of the calculus trope known as Torricelli's trumpet. Nor was this result seen as counterintuitive at the time of its discovery in the 17th century, contrary to many commonplace historical narratives. Transcript Torricelli's trumpet is not counterintuitive. Your calculus textbook lied to you. You've probably heard of this cliché…
I like this rant: I never found Gabriel's horn / Torricelli's trumpet to contradict my intuition, though it's a fun example. intellectualmathematics.com/blog/torricellis-trumpet...
ICYMI there's a new episode of @viktorblasjo.bsky.social's podcast out this week, first new episode in over a year. A fun listen as always
Today I learned (ht Viktor Blasjo) how Huygens summed the reciprocals of the triangular numbers. He regrouped the series and showed that it equals the geometric series 1+1/2+1/4+... = 2, like so!
Sometimes 1 30 was written "1 and ½" to emphasise that 1½ was meant, not 90. Another method of disambiguation was by the size of the characters: a 1 written bigger represents 60, etc. See Neugebauer, Exact sciences in antiquity, pp. 19-20.
New Medieval Books: The Optics of Ibn al-Haytham Books IV-V www.medievalists.net/2024/08/new-... #books
My book in the Cambridge Elements series on "Mathematical Rigour and Informal Proof" is out today! It's free to download for two weeks, so please share it widely with anyone who may be interested. 🥳🎉
www.cambridge.org/core/element...
🥁: Historian of mathematics, famous contrarian and "Intellectual Mathematics" podcaster @viktorblasjo.bsky.social is now on Bluesky! #histsci