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What did Jacobi, who lived before Riemann, have to do with the equation and theorem named after him in Riemannian geometry?
In Riemannian geometry we have two very important things named after Jacobi: the Jacobi equation $J''=R(\gamma',J)\gamma'$ and Jacobi's theorem which states geodesics never minimize past conjugate points. Why is Jacobi's name attached to this…
Ryan Unger
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What is the most ancient civilization that used base-16 (hexadecimal) number system?
What is the first or most ancient civilization to use a base-16, hexadecimal number system?
Geremia
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When did the estimates of planetary distances made between Ptolemy and Copernicus produce the pattern suggesting heliocentrism?
Two patterns in the structure of the Ptolemaic model make the transformation of coordinates to the Copernican model seem "natural" to modern eyes:
the alignment of the radii of the (second) epicycles for outer parents and the deferents of inner…
orome
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6
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Did Newton find the trajectory of a body moving in uniform gravity under the quadratic resistance law (the ballistic problem)?
I'm very confused by contradicting accounts of a supposed solution by Newton to the problem of finding the trajectory of a projectile moving under uniform gravity against resistance that is proportional to the square of the projectile's speed. Some…
user2554
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6
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2 answers
What is the last physics paper or book written in Latin?
What is the last physics paper or book written in Latin? I know Carl Neumann, for example, wrote papers in Latin in the 19th century. Are there any more recently than that?
Geremia
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6
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Origin of Klein's $j$-invariant
Today Klein's $j$-invariant is used in various context's, the most famous one being maybe "Monstrous Moonshine". But what was the original motivation for the study of the $j$-invariant?
Steven
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6
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Grothendieck and elementary topos
I would like to know some references (if any) for the claim that Grothendieck didn't like the idea of elementary topos.
tttbase
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history of backpropagation
Has anybody read or have access to
Alex Andrew
Significance Feedback in Neural Nets
Report of Biological Computer Laboratory, University of Illinois, Urbana, IL
GM-10718-03
TR No 5
September 1965
pages 1--12
and can confirm the contribution…
Gottfried William
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What are the earliest known accounts of the demarcation problem (science versus pseudo science)?
The demarcation problem, i.e. the problem of differentiating science from pseudo science has been on my mind recently. This might be considered a philosophy topic for philoSE but since my question has mostly historical character and related…
MM8
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Who derived $\int_{0}^{\infty} \mathrm{e}^{-x^2}\, dx = \frac{\sqrt \pi}{2}$?
I want to know who derived
$$\int_{0}^{\infty} \mathrm{e}^{-x^2}\, dx = \frac{\sqrt \pi}{2}$$ In school, our book mentioned that Euler proved this result. But on Math Stack Exchange, some people say that Laplace was the first person to derive this…
MrYouMath
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6
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1 answer
Who invented the concepts of potential and kinetic energy?
Who invented potential and kinetic energy ?
Was it Newton ?
Or someone else ?
I have the impression Newton used those ideas but they already existed.
mick
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6
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History related to the "2 litres of water per day" theory
Most people (including doctors) say and also newspapers states that an average person should drink 2 litres (approximately 8 glasses) of water per day.
Even though this is very popular I have heard about this many times, I have never actually heard…
The Artist
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When was the airless void above the earth discovered?
For a very long time, people had no reason to believe that an airless void could exist in nature at all, whether above the earth or anywhere else.
According to Descartes, in his 1633 work The World, the world is already full of matter, whether…
Joe
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Who discovered the "Comet" as a celestial object?
Who first discovered that comets were physical objects with a Keplerian orbit?
Was this accidentally discovered or was it discovered as part of an intentional effort by astronomers after they established facts about Sun, Earth, other planets, moon,…
Amit Tyagi
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Who said “Either you speak maths or you speak nonsense?”
I am in the process of preparing a lecture and remember that some of the Gods (highly esteemed researchers of the past) said, “Either you speak maths or you
speak nonsense.” Perhaps is was “Either you talk maths or you
talk nonsense.”
Any idea of…
user4215