A way to defined geometry without talking about coordinates, i.e. like Euclid's Elements, notably Euclid's postulates, as opposed to Descartes's Real coordinate space.
This dude mentored Enrico Fermi in high school. Ciro Santilli added some info to Fermi's Wikipedia page at: en.wikipedia.org/w/index.php?title=Enrico_Fermi&type=revision&diff=1050919447&oldid=1049187703 from Enrico Fermi: physicist by Emilio Segrè (1970):
In 1914, Fermi, who used to often meet with his father in front of the office after work, met a colleague of his father called Adolfo Amidei, who would walk part of the way home with Alberto [Enrico's father]. Enrico had learned that Adolfo was interested in mathematics and physics and took the opportunity to ask Adolfo a question about geometry. Adolfo understood that the young Fermi was referring to projective geometry and then proceeded to give him a book on the subject written by Theodor Reye. Two months later, Fermi returned the book, having solved all the problems proposed at the end of the book, some of which Adolfo considered difficult. Upon verifying this, Adolfo felt that Fermi was "a prodigy, at least with respect to geometry", and further mentored the boy, providing him with more books on physics and mathematics. Adolfo noted that Fermi had a very good memory and thus could return the books after having read them because he could remember their content very well.
Ciro Santilli really likes guys like this. Given that he does not have the right genetics, conditions and temperance for scientific greatness in this lifetime, he dreams of one day finding his own Fermi instead.
Genius: Richard Feynman and Modern Physics by James Gleick (1994) mentions several times how Richard Feynman was a reader of the encyclopedia. E.g. in youtu.be/ivxkd98mDvc?t=50 Richard's sister also talks about it.
Then the Internet came along and killed it.
The motivation model for collaborators was simple: to get famous. To be able to be selected contribute an article meant that you knew something or two! There was some physicist Ciro read the biography of who was really glad to be able to write an article on the encyclopedia after having worshiped it for so long, TODO find the reference.
While this is somewhat a part of Wikipedia motivation, it is much less so because there is no single article authorship. This is something OurBigBook.com aims to improve.
Although transistors were revolutionary, it is fun to note that they were just "way cheaper and more reliable and smaller" versions of exactly the main functions that a vacuum tube could achieve
The Einstein summation convention works will with partial derivatives and it is widely used in particle physics.
In particular, the divergence and the Laplacian can be succinctly expressed in this notation:
In order to express partial derivatives, we must use what Ciro Santilli calls the "partial index partial derivative notation", which refers to variables with indices such as , , , , and instead of the usual letters , and .
See also: e-learning website.
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