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Tangente

Amazing Math

Surprising or counterintuitive mathematical results and proofs

This papyrus buried by Vesuvius in 79 AD was read unopened
Math History

This papyrus buried by Vesuvius in 79 AD was read unopened

Researchers have succeeded in reading a papyrus scroll charred by Vesuvius in 79 AD, using tomography, phase contrast, and artificial intelligence.

L'équipe TangenteJul 9, 2026
Busy Beaver: the function beyond all computability
Logic Cases

Busy Beaver: the function beyond all computability

The Busy Beaver function grows faster than any computable function. Discover why some numbers are mathematically inaccessible.

La rédaction de TangenteApr 30, 2026
Two locally identical yet different tori break 150 years of geometry
News

Two locally identical yet different tori break 150 years of geometry

Two tori plainly impossible to tell apart locally yet topologically distinct: a discovery that breaks a rule geometry has accepted for 150 years.

Martine BRILLEAUDApr 23, 2026
Ackermann-Péter function: recursion without bounds
Amazing Math

Ackermann-Péter function: recursion without bounds

With a surprisingly simple definition, the Ackermann–Péter function generates numbers of a staggering size. This mathematical construction, born out of research into computability, shows how quickly a recursive procedure can exceed all the usual bounds.

Angelo LaplaceApr 22, 2026
Mersenne primes: discover perfect numbers
Amazing Math

Mersenne primes: discover perfect numbers

The search for Mersenne primes very quickly leads us to examine gigantic numbers.

Daniel LignonApr 22, 2026
The Boltzmann equation: from molecular chaos to macroscopic equilibrium
Amazing Math

The Boltzmann equation: from molecular chaos to macroscopic equilibrium

Formulated in 1872 by the Austrian physicist Ludwig Boltzmann (1844–1906), this equation describes how a gas or fluid evolves toward equilibrium. It bridges molecular collisions at microscopic scales and the macroscopic world.

Daniel LignonApr 22, 2026
Regular polygons with integer-coordinate vertices: one proof for all n
Knowledge

Regular polygons with integer-coordinate vertices: one proof for all n

Discrete geometry is a recent field of research concerned with "discrete objects," such as graphs and tilings. But it also offers a fresh perspective on problems that are difficult to solve in a continuous setting, including the existence of regular polygons with integer-coordinate vertices.

Denise GrenierApr 22, 2026
Integer points on a line: methods of solution
Knowledge

Integer points on a line: methods of solution

Many problems in discrete geometry are simply stated and can be used in teaching to make certain concepts easier to understand. Searching for points with integer coordinates on a line naturally leads to applications of theorems from number theory.

Denise GrenierApr 22, 2026
Moving on the discrete plane: generating sets and minimality
Knowledge

Moving on the discrete plane: generating sets and minimality

Exploring how one can move around a grid leads to the concepts of generating sets and minimality. This example shows the power of discrete geometry as a tool for better visualizing and exploring complex ideas from classical geometry or algebra.

Cécile Ouvrier-BuffetApr 22, 2026
Knuth and Conway notations for mind-boggling numbers
Maths and History

Knuth and Conway notations for mind-boggling numbers

When it comes to representing extremely large numbers, the standard operations, including exponentiation, are no longer enough. With considerable imagination, Donald Knuth and John Conway devised notations to overcome this limitation.

Angelo LaplaceApr 22, 2026
Skewes's numbers: enormous bounds in number theory
History and Culture

Skewes's numbers: enormous bounds in number theory

Skewes's numbers are among the large numbers encountered in arithmetic.

Daniel LignonApr 22, 2026
Discrete lines: the birth of a new geometry
Knowledge

Discrete lines: the birth of a new geometry

Problems involving representation on a pixelated screen belong to discrete geometry. But beyond mere aesthetic considerations, are these new subjects of study—including discrete lines—tools for exploring Euclidean geometry more deeply, or objects of a new geometry?

Cécile Ouvrier-BuffetApr 22, 2026
666: When the devil shows up in math | Tangente
Math for everyone

666: When the devil shows up in math | Tangente

From the biblical 666 to the Belphegor number, certain numbers send a shiver down the spine… and bring a smile to mathematicians' faces. Behind these "cursed" objects, the creativity and ingenuity of recreational mathematics run wild, ranging from number games to diabolical curiosities.

Fabrice ArnaudDec 16, 2025
Mathematical properties of 2026 | Tangente
Math for everyone

Mathematical properties of 2026 | Tangente

Let's not break with our start-of-year tradition and explore together a few charming quirks of the new vintage!

Fabien AOUSTINDec 16, 2025
Vampire numbers and their fangs | Tangente
Math for everyone

Vampire numbers and their fangs | Tangente

Yes, vampire numbers really do exist! And they have fangs!

Daniel LignonDec 15, 2025
Parasitic numbers and permutations | Tangente
Math for everyone

Parasitic numbers and permutations | Tangente

How do you multiply 105,263,157,894,736,842 by 2? Simple: just move the final digit, 2, to the front of the number, giving 210,526,315,789,473,684. And there you have it!

Daniel LignonDec 15, 2025
Conway's power trains | Tangente
Math for everyone

Conway's power trains | Tangente

Power trains are iterated functions introduced by Conway.

Daniel LignonDec 15, 2025
Multiplicative persistence of numbers | Tangente
Math for everyone

Multiplicative persistence of numbers | Tangente

Adding or multiplying together the digits of an integer is an activity a curious child might feel like doing. But they probably have no idea that it is the source of problems still unsolved in 2025!

Robert FerréolDec 15, 2025
Prime numbers and changing digits | Tangente
Math for everyone

Prime numbers and changing digits | Tangente

Unlike some composite numbers, it is hard to tell whether a number is prime just by looking at it. So what happens to a prime number if we make a change to its digits — for example, by permuting them or removing some of them? Can it stay prime? Or, on the contrary, does it stop being prime?

Daniel LignonDec 15, 2025
Narcissistic numbers and their secrets | Tangente
Math for everyone

Narcissistic numbers and their secrets | Tangente

In the 1960s, while teaching at the University of Rochester in New York State, Mike Armstrong became particularly interested in k-digit numbers equal to the sum of the kth powers of their digits.

Fabien AOUSTINDec 15, 2025