# Tag Info

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### Why do we call Tycho Brahe by his first name?

The short answer is that this is how he referred to himself. He was born Tyge Otteson Brahe but at the age of 15 (1561) changed 'Tyge' to Latinized 'Tycho', see Redd's biography of Tycho and Thoren's ...
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### Emmy Noether or Emmy Nöther?

Taking a look at her 1933 paper in Mathematische Annalen one sees: Similarly for a 1923 paper: From a glance at a few other papers, she (or all the journals) used "Noether" for her last ...
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### Why did angular momentum get the letter L

I just want to comment that the agreement on letters, by which we write $\frac d{dt}\mathbf L=\mathbf M$ for the law of angular momentum, must have come very late -- after 1964. As evidence, note that ...
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### Contributions to chemistry from medieval Arabia

Jabir ibn Hayyan was the first to describe processes such as liquefaction, crystallisation, distillation, purification, oxidisation, evaporation and filtration. He also did an early classification of ...
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### What was the Big Bang model originally called?

Lemaitre, who proposed the first version of "Big Bang" in 1927, called it Primeval Atom hypothesis since late 1930s, notably in the 1950 book of this name. However, it was rather different ...
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### Why is one meter as long as it is?

This number has no significance. Its origin is historical. Originally the meter was defined as 1/40,000,000 part of the Paris meridian. Based on the measurement of this meridian, they made a standard ...
• 42.7k
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### Why is there no named unit for momentum but there is one for energy?

There is a historical reason. But it was not a fluke of history, the underlying reason is that energy comes up in non-mechanical (thermal, electric) contexts whereas momentum does not. Derived ...
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### When did the names of scientists first become the names of scientific units?

History of the metric system - Wikipedia says: In 1861, Charles Bright and Latimer Clark proposed the names of ohm, volt, and farad in honour of Georg Ohm, Alessandro Volta and Michael Faraday ...
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### Did anybody know Pi well enough in 1592 to celebrate Pi day?

There could not have been a $\pi$ day in 1592 regardless of calendar conventions for the simple reason that there was no such thing as $\pi$ back then. The symbol was introduced by William Jones in ...
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### Why are étale morphisms called "étale"?

From Milne's site: There are two different words in French, "étaler", which means spread out or displayed and is used in "éspace étalé", and "étale", which is rare ...
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### Who invented the integers?

Very few (if any) mathematicians before Cantor thought of the SET of integers. Certainly for Euclid it was completely evident that the sequence of integers extends without limit. (He actually has a ...
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### Why was delta ($\Delta$) chosen to represent change of a quantity?

There was a related question on Math.SE, which Mauro Allegranza answered with reference to Cajori's classic History of Mathematical Notations (v.II, p.205). It is a great source and is freely ...
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### What is the etymology behind sine, cosine, tangent, etc.?

Victor Katz is not a linguist and a lot of what he says in the quoted extract is wrong: for example that “Arabic is written without vowels” and that the word in question is spelt “jb”. In fact it is ...
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### Are there widely accepted math symbols using non-Latin alphabets or characters other than Greek and Hebrew?

The letter Ш (sha) of the Cyrillic alphabet is widely accepted in theoretical computer science as the symbol for the shuffle product, which gives the shuffle algebra. The same letter is also used to ...
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### What is the status of the three crises in the history of mathematics?

No, it is not widely accepted. The language of "crises" is rather obsolete and mostly reflects the attitudes of the early 20th century projected backwards. At that time, the contemporaries did indeed ...
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### What is the etymology behind sine, cosine, tangent, etc.?

For sinus, see : Victor Katz, A History of Mathematics (3rd edition, 2008), apge 253 : The English word “sine” comes from a series of mistranslations of the Sanskrit jya-ardha (chord-half). ...
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### Who started calling the matrix multiplication "multiplication"?

The same person who introduced it, Cayley. Sylvester first used the term "matrix" (womb in Latin) for an array of numbers in 1848, but did not do much with it. Cayley started developing matrix algebra ...
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### Who invented the integers?

Actually when we say Integer today, we mean set of all positive whole numbers, negative whole numbers and zero. But this complete set was not discovered/invented in a day. People were working with ...
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### How did we come up with the name "atomic bomb"?

I'm going to try to answer the question you end with, "Why has atomic bomb instead of another better term become the predominant term?", rather than the question in your title, because that's the ...
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### Who first used the word "calculus", and what did it describe?

According to Carl B. Boyer, "The history of the calculus and its conceptual development", Dover Publications 1959, page 98, The improved notation led also to methods which were so much more facile ...
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### Why are canonical coordinates canonical?

Such coordinates were called canonical because they are those in which equations of motion (or, of the hamiltonian flow of a function $H$) take the “canonical form”  \frac{dq_i}{dt}=\frac{\partial H}...
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### Who said $\pi$ is a constant since it is not even a real number?

This question is based on a misunderstanding. The statement that $\pi$ is constant has precise meaning: $\pi$ is a ratio of the length of circumference to the length of diameter. The statement that it ...
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### What is the origin of "an algebra" as in vector space with multiplication?

Actually, it happened in the reverse order, algebras came first, and vector spaces only later. For the vector space story see When did people start viewing a matrix as a linear transformation between ...
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### Why do we call a linear mapping "linear mapping"?

The theory of Linear Algebra, along with the associated concept of linear mapping, was named as "linear" by its creator, Hermann Graßmann, which he developed in his 1844 linear algebra manifesto, Die ...
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### Why do we say "Matrices" and "Vertices", but "Complexes" rather than "Complices"?

Because unlike vertex, matrix or simplex, that came directly from Latin and have primarily mathematical uses, complex was borrowed through French around 1650s, with the meaning "a whole comprised of ...
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### Why is the letter $\vec{r}$ used for position?

The $r$ is for "radius", and in particular, describes the radial vector from the origin to the location described by the vector. This is sensible because some sort of polar or spherical coordinates ...
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### When was the term "corollary" first used in proofs?

"Corollary" is similar to the word "bonus": a little extra (i.e. an extra proposition coming from a demonstration). The term Euclid uses is πόρισμα "porism," which ...
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### Are there widely accepted math symbols using non-Latin alphabets or characters other than Greek and Hebrew?

There are several non-alphabetic symbols, the best known is the integral sign $\int$ and the Weierstrass $P$-function $\wp$. To be sure their origins are letters of Latin alphabet, but they are ...
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It is sometimes asserted that $\varnothing$ for the empty set was introduced by Bourbaki using a Danish and Norwegian letter. EDIT: The source is the Weil autobiography, cited in Jeff Miller's ...