Amazing Math
Surprising or counterintuitive mathematical results and proofs
OuLiPo: Mathematics inspires literature | Tangente
On November 24, 1960, Raymond Queneau, a writer with a passion for mathematics, and François Le Lionnais, a mathematician with a love of literature, founded Oulipo (the Workshop of Potential Literature), together with mathematicians such as Paul Braffort and Claude Berge, as well as Jacques Bens, Jean Lescure and Marcel Duchamp. They would later be joined by Georges Perec, Luc Étienne, Jacques Roubaud, Italo Calvino and others.
An illustrious line of descendants
It all began with a football to which Euler's formula was applied. Why does the constant 2 appear on the right-hand side? To find out, we follow in the footsteps of Henri Poincaré, André Weil and… Alexander Grothendieck.
From sentence to formula
Before the 20th century, everyday language played a prominent role in mathematical writing. Did that necessarily make it easier to read? How did the balance between descriptive sentences and concise formulas emerge?
A “little” theorem for major advances
Fermat's “little” theorem is surely one of the most fruitful results in arithmetic. Ever since it was first stated in 1640, mathematicians have made constant use of it. Euler even proposed a sweeping generalization. Let's take a closer look…
Fermat and his little theorem: history | Tangente
In the 17th century, Pierre de Fermat, though not a professional mathematician, was one of the pioneers of number theory. Less famous than his "last" theorem, whose proof has yielded more applications than the statement alone, his "little" theorem is immensely useful to us.
Psychological experiments in arithmetic
Like any other scientist, a mathematician makes use of experiments. But these do not necessarily resemble those conducted in other sciences: carried out mentally or on a sheet of paper, they are usually psychological in nature!
In search of friends
Integers never cease to fascinate us: divisibility raises some formidable questions, as several conjectures about perfect numbers attest. Here, experimenting with a computer is a valuable aid in the hunt for counterexamples.
Those darn paradoxes! (4): A Mathematical Brief | Tangente
Every claim must be proved properly.
Those pesky paradoxes! (3) — Maths brief | Tangente
Logic may sometimes try to deceive us—beware!
Those darn paradoxes! (2) — Mathematical note | Tangente
God exists because mathematics is consistent, and the devil exists because we cannot prove it...
Holy paradoxes! (1): A mathematical brief | Tangente
Paradox is to logic what experiment is to the physicist: it allows us to adjust theory in response to the question posed by an alarming result. It is a springboard for the mind.
The rules of infinity
You cannot play with sets without abiding by certain rules...
From a collection of objects to a set
A set can be defined extensionally or intensionally. Constructing the natural numbers then becomes an easy but instructive exercise. Yet beware the apparent simplicity of a set viewed as a mere collection of objects: paradoxes lurk...
An unsettling approach to mathematics | Tangente
Set theory, iconoclastic in Cantor's day, has become universal. Nothing like it had been seen since Euclid: it provides a foundation for mathematics! That foundation seemed solid—until paradoxes emerged. So what is this highly controversial mathematical construction?
Paradoxes of infinity — Math brief | Tangente
Infinity must be handled with care, lest we lose ourselves (in its paradoxes)...
The axiom of choice
Being able to choose an element from a set seems natural. But it is truly natural only when the set is finite. Beyond that, an axiom is needed before we can choose! Some consequences of this axiom are surprising, so… should we accept it?
Georg Cantor: from finite to infinite
To extend useful results about finite sets to infinite sets, Cantor defined equality of cardinalities in terms of bijections, and hence inequality in terms of injections and surjections. Remarkably, this yields an order relation.
Pythagorean triples
In a right triangle, the square of the hypotenuse equals the sum of the squares of the two sides forming the right angle. When three integers satisfy this relation, they are called a Pythagorean triple. What are these numbers, and how can they be characterized?
Pythagoras: much more than a theorem
Pythagoras is more than the name of a famous theorem: he inspired an entire philosophical tradition that would influence not only mathematics and astronomy but music itself. Beyond the sciences, history has not heard the last of the "long-haired Samian"!
A few classic paradoxes
Paradoxes are fun to explore and require no specialist knowledge. They help us better understand rationality, truth, probability, uncertainty and information… along with the many theories built around them. Prepare to be surprised by a few spectacular classics.