Girard Desargues (French: [dezaʁɡ]; 21 February 1591 – September 1661) was a French mathematician and engineer, who is considered one of the founders of projective geometry. Desargues' theorem, the Desargues graph, and the crater Desargues on the Moon are named in his honour. Born in Lyon, Desargues came from a family devoted to service to the French crown. His father was a royal notary, an investigating commissioner of the Seneschal's court in Lyon (1574), the collector of the tithes on ecclesiastical revenues for the city of Lyon (1583) and for the diocese of Lyon. Girard Desargues worked as an architect from 1645. Prior to that, he had worked as a tutor and may have served as an engineer and technical consultant in the entourage of Richelieu. As an architect, Desargues planned several private and public buildings in Paris and Lyon. As an engineer, he designed a system for raising water that he installed near Paris. It was based on the use of the epicycloidal wheel, the principle of which was unrecognized at the time. His research on perspective and geometrical projections can be seen as a culmination of centuries of scientific inquiry across the classical epoch in optics that stretched from al-Hasan Ibn al-Haytham (Alhazen) to Johannes Kepler, and going beyond a mere synthesis of these traditions with Renaissance perspective theories and practices. His work was rediscovered and republished in 1864. A collection of his works was published in 1951, and the 1864 compilation remains in print. One notable work, often cited by others in mathematics, is "Rough draft for an essay on the results of taking plane sections of a cone" (1639). Late in his life, Desargues published a paper with the cryptic title of DALG. The most common theory about what this stands for is Des Argues, Lyonnais, Géometre (proposed by Henri Brocard). He died in Lyon. (Wikipedia).
Lagrange Bicentenary - Cédric Villani's conference
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From playlist Bicentenaire Joseph-Louis Lagrange
Orthocenters exist! | Universal Hyperbolic Geometry 10 | NJ Wildberger
In classical hyperbolic geometry, orthocenters of triangles do not in general exist. Here in universal hyperbolic geometry, they do. This is a crucial building block for triangle geometry in this subject. The dual of an orthocenter is called an ortholine---also not seen in classical hyperb
From playlist Universal Hyperbolic Geometry
Lagrange Bicentenary - Jacques Laskar's conference
Lagrange and the stability of the Solar System
From playlist Bicentenaire Joseph-Louis Lagrange
Rene Descartes is perhaps the world’s best known-philosopher, in large part because of his pithy statement, ‘I think therefore I am.’ He stands out as an example of what intellectual self-confidence can bring us. Please subscribe here: http://tinyurl.com/o28mut7 If you like our films take
From playlist WESTERN PHILOSOPHY
algebraic geometry 16 Desargues's theorem
This lecture is part of an online algebraic geometry course, based on chapter I of "Algebraic geometry" by Hartshorne. It covers Desargues's theorem and duality of projective space.
From playlist Algebraic geometry I: Varieties
Paul Ricœur on Descartes (1987)
A few clips of Paul Ricœur discussing Descartes. He explains why the birth of modern thought goes back to Descartes. For unlike the Greek world and Middle Ages, which took the notion of Being and Substance as their guide, it is subjectivity and the thinking subject which became the new val
From playlist Shorter Clips & Videos - Philosophy Overdose
9. Don Quixote, Part I: Chapters XXVII-XXXV (cont.)
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Les 10 ans du Groupe Calcul - Laurent Desbat, TIMC-IMAG, Université Fourier, Grenoble
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From playlist Les 10 ans du Groupe Calcul
Fermat's Christmas theorem: Visualising the hidden circle in pi/4 = 1-1/3+1/5-1/7+...
NEW (Christmas 2019). Two ways to support Mathologer Mathologer Patreon: https://www.patreon.com/mathologer Mathologer PayPal: paypal.me/mathologer (see the Patreon page for details) Leibniz's formula pi/4 = 1-1/3+1/5-1/7+... is one of the most iconic pi formulas. It is also one of the
From playlist Recent videos
Art Trip: Columbus, Indiana | The Art Assignment | PBS Digital Studios
Visit the architectural mecca of Columbus, Indiana, to bask in the mid-century glory of Eliel and Eero Saarinen’s masterpieces and a series of new and innovative installations by renowned designers. We explore the first exhibition of Exhibit Columbus, an annual exploration of architecture,
From playlist Art Trip
Pourquoi ont-ils choisi la voie des mathématiques?
Interview de deux mathématiciens - Jean-Claude THOMAS et Pascal LAMBRECHTS - lors de leur séjour au CIRM en juin 2012. Programme proposé par le CIRM - Centre International de rencontres Mathématiques.
From playlist Lagrange Days at CIRM
Crystal Critters - salt structures that come to life!
Samantha McBride (MIT) and Henri Girard (MIT) explain how they accidentally discovered a new fluid dynamics phenomena where the evaporation of salt water forms amazing creatures such as a 'jellyfish', 'crab', 'elephant' and 'droid'. Research by Samantha McBride and Henri Girard at MIT. I
From playlist Fluid Dynamics
Projective geometry | Math History | NJ Wildberger
Projective geometry began with the work of Pappus, but was developed primarily by Desargues, with an important contribution by Pascal. Projective geometry is the geometry of the straightedge, and it is the simplest and most fundamental geometry. We describe the important insights of the 19
From playlist MathHistory: A course in the History of Mathematics
Introduction to Projective Geometry | WildTrig: Intro to Rational Trigonometry | N J Wildberger
A first look at Projective Geometry, starting with Pappus' theorem, Desargues theorem and a fundamental relation between quadrangles and quadrilaterals. This video is part of the WildTrig series, which introduces Rational Trigonometry and applies it to many different aspects of geometry.
From playlist WildTrig: Intro to Rational Trigonometry
The perspective image of a square II -- more Projective Geometry! | FMP 18b | N J Wildberger
We delve further in Projective Geometry in pursuit of the problem of showing that a general quadrilateral is the perspective image of a square. To prepare the scene, we investigate the role of vanishing points and lines at infinity, first in the two-dimensional case when we project one lin
From playlist Famous Math Problems
The ugly psychology behind scapegoating | Luke Burgis | Big Think
The ugly psychology behind scapegoating, with Luke Burgis Subscribe to Big Think on YouTube ►► https://www.youtube.com/c/bigthink Up next ►► How to learn from failure and quit the blame game | Alisa Cohn | Big Think https://youtu.be/BMRq38ECmFc Did you know that our desires are not enti
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Hugo Duminil-Copin - La marche aléatoire auto-évitante
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From playlist Les probabilités de demain 2016