ELISABETH BUSSER
226 articles published in Tangente
Math for everyoneN°80Nov 17, 2021Symmetries that leave objects invariant
In geometry, what could be more natural than to seek, for each object, the transformations that leave it unchanged? This means dissecting those transformations and identifying the object's symmetries—and, surprise, groups emerge quite naturally...
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Games and ChallengesN°80Nov 17, 2021The Rubik's Cube group
The Rubik's Cube is a hugely popular puzzle among children and adults alike. This object, too, has its own group: all the isometries that leave it invariant.
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Math for everyoneN°202Oct 12, 2021Divisibility without calculations
We cannot forget them: they are ingrained in our memories from elementary and high school—but is that really certain? Do we still remember all those divisibility tests our mathematics teachers drummed into us so often?
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Math for everyoneN°202Oct 12, 2021A history of modular arithmetic
The idea of working with the remainders obtained when numbers are divided by certain integers, rather than with the numbers themselves, gradually gained ground. Gauss formalized the idea with his notion of congruence, giving rise to modern modular arithmetic. Congruences have quite a history!
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History and CultureN°79Aug 24, 2021Activities at the Institut Henri-Poincaré
The Poincaré Seminar on theoretical physics takes place in a venue worthy of the name: the Institut Henri-Poincaré, in Paris's 5th arrondissement, at the heart of the Latin Quarter.
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History and CultureN°79Aug 24, 2021The Henri Poincaré prize
The Henri Poincaré Prize, sponsored by the Daniel-Lagolnitzer Foundation in partnership with the International Association of Mathematical Physics, now ranks among the major scientific prizes.
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Games and ChallengesN°201Aug 23, 2021Problem-writing competition
To mark the publication of issue 200, Tangente organized a problem-writing competition. Nine of the forty-three puzzles submitted received prizes, but many others deserved one too. We asked the jury members to single out their personal favorites.
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Math for everyoneN°201Aug 19, 2021Using barycenters in proofs
First used in physics and mechanics, the concept of the barycenter has proved a rich source of mathematical results. Alignment, incidence, construction and locus problems: geometry can hardly do without it!
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History and CultureN°200Jun 14, 2021Another Goncourt for another mathematician
Mathematics scored twice in 2021, with two Goncourt Prizes.
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History and CultureN°200Jun 11, 2021Napoleon'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).
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Math for everyoneN°78May 20, 2021Computer geometry
Although computer drawing had been possible since the 1970s, so-called "dynamic geometry" software did not become widespread until the 1980s.
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Math for everyoneN°78May 20, 2021Why a sound method matters
Never known how to "get started" on a straightedge-and-compass geometry problem? What matters, which points should you introduce, and which line should you construct? The classic, tried-and-tested method of analysis and synthesis provides a sound approach to such construction problems.
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