Famous figures
Portraits of famous mathematicians, historical and contemporary
Alexis Clairaut: A forgotten light of mathematics | Tangente
Alongside Leonhard Euler and Jean Le Rond d’Alembert, Alexis Clairaut was one of the greatest mathematicians of the Enlightenment. Though little known today, he played a fundamental role in validating Newton's theory of universal gravitation.
Sylvie Méléard wins the Irène-Joliot-Curie Prize | Tangente
A specialist in probability theory, particularly stochastic processes, Sylvie Méléard has spent the past twenty years applying mathematical models to living systems: changes in population size over time (such as bacterial growth), the proportion of an allele in a population, and genetic evolution (such as antibiotic resistance).
Jacques Roubaud: tribute to a poet-mathematician | Tangente
Following Oulipo's time-honored formula, Jacques Roubaud is now excused from its meetings on account of his death, which occurred this past December 5, his 92nd birthday.
Kepler, or the defeat of the circle
Kepler's first law states that planets follow elliptical orbits around the Sun. How can this be proved with the bare minimum of theory? To answer this question, physicist Richard Feynman produced a little gem of classical geometry applied to celestial mechanics.
A question of circumference
You might expect calculating the perimeter of an ellipse—a fairly ordinary shape—to be straightforward. Yet it is a problem on which mathematicians have displayed extraordinary ingenuity. And in the formula contest, Ramanujan wins!
Condorcet’s Enlightenment fight against slavery | Tangente
In his Réflexions sur l’esclavage des nègres (Reflections on Black Slavery), published in 1781 under the pseudonym Pastor Joachim Schwartz ("black" in German), Condorcet opposed slavery, which he regarded as a fundamental violation of human rights, and denounced the contradictions and injustices bound up with the enslavement of Black people.
Condorcet, champion of women's suffrage | Tangente
A few years before the Revolution began, Condorcet was the first French writer to make the case for women's voting rights in his Lettres d’un bourgeois de New-Haven (1787).
Condorcet's paradox explained | Tangente
From Lewis Carroll to Kenneth Arrow, the famous Condorcet paradox has generated a great deal of discussion.
Condorcet, theorist of electoral procedures | Tangente
Condorcet is recognized as one of the pioneers in the theory of electoral systems, alongside his contemporary, the Chevalier de Borda. Both thinkers brought a fundamental idea to light: the method used to elect a candidate has a decisive influence on the outcome.
From political arithmetic to social mathematics | Tangente
Condorcet is not the first to seek to apply mathematics to public life. Yet he sets himself radically apart from his predecessors—and lays claim to that distinction—by coining the phrase "social mathematics."
Condorcet judged by his peers | Tangente
Condorcet always took an interest in analysis, but accounts and assessments of his mathematical work varied widely. Although he bounced back after the Académie’s unfavorable judgment of his first paper, the 19th century proved much harsher.
Condorcet’s project for a numeral system | Tangente
During the French Revolution, the National Constituent Assembly decided to standardize weights and measures and entrusted several scientists, including Condorcet, with determining the length of what would become the metre. In the same spirit of rationalization and simplification, Condorcet turned his attention to the education of young children.
Condorcet: mathematics for citizenship | Tangente
Condorcet embraced the ideals of the French Revolution and played an active part in the educational reforms set in motion by the Revolution.
Condorcet, pioneer of scientific skepticism | Tangente
Responding to the vogue for Mesmerism—what we would now call a pseudoscience—Condorcet may be regarded as a pioneer of scientific skepticism. His analyses remain as relevant and timely as ever.
Sophie de Condorcet, a figure of the Enlightenment | Tangente
Born around 1763, Sophie de Grouchy married Condorcet, whom she had met at the home of her uncle and mentor, President Mercier du Paty.
Condorcet and the transmission of knowledge | Tangente
At the end of the preface to his Essais d’Analyse, Condorcet includes the Latin quotation "vice fungar cotis, acutem reddere quae ferrum valet, exsors ipsa secandi," from Horace’s Ars Poetica (line 305).
Julie de Lespinasse and d'Alembert's salon | Tangente
Julie de Lespinasse, a highly cultured woman and close friend of d’Alembert, opened a salon in 1764 at the corner of rue de Bellechasse and rue Saint-Dominique.
Condorcet: a true Enlightenment mathematician | Tangente
Although Condorcet is best known today as a philosopher, he began his career as a mathematician. A precocious polymath, mathematics also led him to politics and philosophy.
Polygonizing a number: histonumbers and Theodorus' spiral | Tangente
Several methods can be used to associate a polygon with a given number.
Vertex figures: duality and Platonic solids | Tangente
A polyhedron is an assembly of polygons with vertices, edges and faces, arranged so that every edge is shared by two faces.