Daniel Lignon
91 articles published in Tangente
History and CultureN°94May 05, 2025Erdős and old age
A few years before turning sixty, Erdős began adding strange initials to his signature as a reminder of the passage of time.
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History and CultureN°94May 05, 2025More than 600 problems still open
Throughout his life, in papers written either alone or with collaborators, Erdős posed a great many problems. He solved some of them—but far from all.
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History and CultureN°94May 05, 2025Editorial
Paul Erdős posed or solved hundreds of problems in almost every field. He was nicknamed "the prince of problem solvers and the absolute monarch of problem posers" by Ernst Straus, one of his colleagues.
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Math for everyoneN°222Feb 10, 2025Evaluating education policies
The international TIMSS survey (Trends in International Mathematics and Science Study) has just released its results for 2023.
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Games and ChallengesN°222Feb 10, 2025GIMPS and Mersenne numbers
If you would like to put your computer to work for research, your name might one day be associated with the discovery of a new Mersenne prime…
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History and CultureN°222Feb 10, 2025They found it
Here are a few amateur mathematicians whose names are associated with recent results.
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History and CultureN°222Feb 10, 2025Recognized amateurs
What is an amateur mathematician? Defining one is no easy task, especially since the concept has undoubtedly evolved over time. Nevertheless, we will look at a few examples, both past and present.
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History and CultureN°220Oct 15, 2024Alexandre Grothendieck, mathematics' rebel legend
On the Radio France website, the programme "Les grandes traversées" explores the lives of people who embarked on momentous journeys, whether literal, political or intellectual.
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KnowledgeN°91Aug 24, 2024A train of thought
It took mathematicians a long time to define a convergent sequence without falling into the many logical traps involved. Cauchy's research was among the most important contributions that eventually clarified the matter.
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KnowledgeN°219Aug 22, 2024Approximating functions: not so simple...
When we want to get closer to an object, we try to reduce the distance between us and it. The same applies when "approximating" a function. But matters become more complicated because there are several notions of distance.
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History and CultureN°218Jun 13, 2024Fractal dimension
The construction of fractal objects called for new definitions of distance.
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Math for everyoneN°90May 07, 2024Algebraic numbers among other numbers
Algebraic numbers that count...
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