Famous figures
Portraits of famous mathematicians, historical and contemporary
Archives Henri-Poincaré: history of science | Tangente
A transdisciplinary team built around Henri Poincaré's name and work
Poincaré, the last great polymath | Tangente
Henri Poincaré embodies an ideal of scientific unity: he mastered every field of science in his day. His name remains associated with a staggering number of mathematical ideas, concepts and objects. More than a century after his death, he continues to inspire mathematicians, physicists and philosophers.
Poincaré: a frequent traveler to scientific congresses | Tangente
Henri Poincaré traveled extensively for academic visits, meetings, and lectures.
Poincaré and free inquiry in Brussels | Tangente
"Freedom is to science what air is to an animal; deprived of freedom, science dies of asphyxiation, like a bird deprived of oxygen."
Poincaré's childhood utopian government | Tangente
In 1867, having just visited the Exposition universelle, 13-year-old Henri came up with the idea of establishing a three-part system of government in the large garden at Arrancy, where he spent his holidays: a kind of federation he called Trinasie.
Poincaré's irony about logicism | Tangente
Henri Poincaré regarded experience and intuition as essential to the foundations of mathematics. He was therefore often ironic, even caustic, toward those who relied on abstract logic to provide a foundation for arithmetic
Poincaré vs Hilbert: intuition and logic | Tangente
The debate between Henri Poincaré and David Hilbert illustrates two opposing views of the nature of mathematics.
Tokyo Olympics: a mathematician strikes gold | Tangente
Mathematician Anna Kiesenhofer won a cycling gold medal at the Tokyo Olympic Games.
Jacques Dominioni, painter of geometry | Tangente
The work of the painter Jacques Dominioni (1934–2014) belongs primarily to lyrical abstraction. Yet his mastery of basic geometric forms—lines, circles and the grid structure underlying his paintings—is thought-provoking... and moving. Let's explore the different periods of his artistic output.
Euclid's algorithm, et cetera
A history of arithmetic—or how an algorithm dating from the third century BCE has endured through the ages and evolved to serve modern disciplines, particularly computer science and cryptology.
An Interview with Cédric Villani | Tangente
A 2010 Fields medallist and member of the Académie des sciences, Cédric Villani has become a leading advocate for mathematical culture. In early 2017, following Emmanuel Macron's rise to power, he became an MP for Essonne. What impact has this eminent mathematician's entry into politics had?
The haberdasher's puzzle and Dudeney's puzzle
Any polygon can be cut into finitely many pieces and rearranged to form any other polygon of the same area. This property holds in the plane, but its three-dimensional counterpart is false. It was conjectured by the Hungarian mathematician Farkas Bolyai (1775–1856).
Euler's 36 officers problem | Tangente
In 1779, while the Swiss mathematician Leonhard Euler was at the court of Catherine of Russia, she asked him to investigate a problem that had been circulating in Saint Petersburg for some time, but that no one had managed to solve.
Sylvester's problem | Tangente
In 1893, the British mathematician James Joseph Sylvester (1814–1897) posed the following question in the Educational Times.
Tangente: a catalyst for mathematical culture | Tangente
A magazine devoted to mathematical culture—that is sure to surprise more than a few people! When Tangente arrived in 1987, it transformed the way mathematics was viewed. It inspired some readers to pursue a path they had never considered and others to embark on initiatives to popularize mathematics. Many prominent figures bear witness to this.
Maurice Glaymann, a leading figure in mathematics education | Tangente
Maurice Glaymann was an outstanding figure in French mathematics education.
A Goncourt for a mathematician | Tangente
Mathematics scored twice in 2021, with two Goncourt Prizes.
Napoleon's problem
In this bicentenary year of 2021, let's revisit a result that bears his name. The emperor is said to have had a keen interest in geometry; according to one story, he once discussed the subject with two mathematicians of his day, Joseph Lagrange (1763–1813) and Pierre-Simon Laplace (1749–1827).
Give Euclid his due...
Geometric constructions are central to reasoning in Euclid's The Elements. The various methods of teaching geometry, right up to the present day, claim to follow this approach.
Through Euclid's eyes
Two postulates in Euclid's Elements embody the ideal conception of the straightedge and compass inherited from Plato's realm of Ideas. The Alexandrian scholar built much of plane geometry—and the constructions he bequeathed to us—on these two postulates.