Introduction Updated +Created
ELF is the dominating file format for Linux. It competes with Mach-O for OS X and PE for Windows.
ELF supersedes .coff, which supersedes a.out.
Ladder operator Updated +Created
The operators are a natural guess on the lines of "if p and x were integers".
And then we can prove the ladder properties easily.
The commutator appear in the middle of this analysis.
SHT_NULL Updated +Created
In index 0, SHT_NULL is mandatory. Are there any other uses for it: stackoverflow.com/questions/26812142/what-is-the-use-of-the-sht-null-section-in-elf ?
SHT_SYMTAB on the executable Updated +Created
By default, NASM places a .symtab on the executable as well.
This is only used for debugging. Without the symbols, we are completely blind, and must reverse engineer everything.
You can strip it with objcopy, and the executable will still run. Such executables are called "stripped executables".
SQUID device Updated +Created
Can be used as a very precise magnetometer.
There are high temperature yttrium barium copper oxide ones that work on liquid nitrogen.
Video 1.
Superconducting Quantum Interference Device by Felipe Contipelli (2019)
Source. Good intuiotionistic video. Some points deserved a bit more detail.
Video 2.
Mishmash of SQUID interviews and talks by Bartek Glowaki
. Source.
The videos come from: www.ascg.msm.cam.ac.uk/lectures/. Vintage.
Mentions that the SQUID device is analogous to a double-slit experiment.
One of the segments is by John Clarke.
Video 3.
Superconducting Quantum Interference Devices by UNSW Physics (2020)
Source.
An experimental lab video for COVID-19 lockdown. Thanks, COVID-19. Presented by a cute and awkward Adam Stewart.
Uses a SQUID device and control system made by STAR Cryoelectronics. We can see Mr. SQUID EB-03 written on the probe and control box, that is their educational product.
As mentioned on the Mr. SQUID specs, it is a high-temperature superconductor, so liquid nitrogen is used.
He then measures the I-V curve on an Agilent Technologies oscilloscope.
Unfortunately, the video doesn't explain very well what is happening behind the scenes, e.g. with a circuit diagram. That is the curse of university laboratory videos: some of them assume that students will have material from other internal sources.
Video 4.
The Ubiquitous SQUID by John Clarke (2018)
Source.
Polynomial over a ring Updated +Created
The usual definition of a polynomial is over a field as shown at polynomial over a field.
However, there is nothing in the immediate definition that prevents us from having a ring instead, i.e. a field but without the commutative property and inverse elements.
The only thing is that then we would need to differentiate between different orderings of the terms of multivariate polynomial, e.g. the following would all be potentially different terms:
while for a field they would all go into a single term:
so when considering a polynomial over a ring we end up with a lot more more possible terms.
If the ring is a commutative ring however, polynomials do look like proper polynomials: Section "Polynomial over a commutative ring".
JavaScript with SHAs Updated +Created
There are two types of JavaScript found so far. The ones with SHA and the ones without. There are only 2 examples of JS with SHA:Both files start with precisely the same string:
var ms="\u062F\u0631\u064A\u0627\u0641\u062A\u06CC",lc="\u062A\u0647\u064A\u0647 \u0645\u062A\u0646",mn="\u0628\u0631\u062F\u0627\u0632\u0634 \u062F\u0631 \u062C\u0631\u064A\u0627\u0646 \u0627\u0633\u062A...\u0644\u0637\u0641\u0627 \u0635\u0628\u0631 \u0643\u0646\u064A\u062F",lt="\u062A\u0647\u064A\u0647 \u0645\u062A\u0646",ne="\u067E\u0627\u0633\u062E",kf="\u062E\u0631\u0648\u062C",mb="\u062D\u0630\u0641",mv="\u062F\u0631\u064A\u0627\u0641\u062A\u06CC",nt="\u0627\u0631\u0633\u0627\u0644",ig="\u062B\u0628\u062A \u063A\u0644\u0637. \u062C\u0647\u062A \u062A\u062C\u062F\u064A\u062F \u062B\u0628\u062A \u0635\u0641\u062D\u0647 \u0631\u0627 \u0628\u0627\u0632\u0622\u0648\u0631\u06CC \u06A9\u0646\u064A\u062F",hs="\u063A\u064A\u0631 \u0642\u0627\u0628\u0644 \u0627\u062C\u0631\u0627. \u062E\u0637\u0627 \u062F\u0631 \u0627\u062A\u0651\u0635\u0627\u0644",ji="\u063A\u064A\u0631 \u0642\u0627\u0628\u0644 \u0627\u062C\u0631\u0627. \u062E\u0637\u0627 \u062F\u0631 \u0627\u062A\u0651\u0635\u0627\u0644",ie="\u063A\u064A\u0631 \u0642\u0627\u0628\u0644 \u0627\u062C\u0631\u0627. \u062E\u0637\u0627 \u062F\u0631 \u0627\u062A\u0651\u0635\u0627\u0644",gc="\u0633\u0648\u0627\u0631 \u06A9\u0631\u062F\u0646 \u062A\u06A9\u0645\u064A\u0644 \u0634\u062F",gz="\u0645\u0637\u0645\u0626\u0646\u064A\u062F \u06A9\u0647 \u0645\u064A\u062E\u0648\u0627\u0647\u064A\u062F \u067E\u064A\u0627\u0645 \u0631\u0627 \u062D\u0630\u0641 \u06A9\u0646\u064A\u062F\u061F"
Good fingerprint present in all of them:
throw new Error("B64 D.1");};if(at[1]==-1){throw new Error("B64 D.2");};if(at[2]==-1){if(f<ay.length){throw new Error("B64 D.3");};dg=2;}else if(at[3]==-1){if(f<ay.length){throw new Error("B64 D.4")
Calculus Updated +Created
Well summarized as "the branch of mathematics that deals with limits".
Eliezer Yudkowsky Updated +Created
Elliptic curve group Updated +Created
ENIAC Updated +Created
Endofunction Updated +Created
A function where the domain is the same as the codomain.
Elliptic curve university course Updated +Created
Encyclopedia Galactica Updated +Created
Embedded operating system Updated +Created
Planck's law Updated +Created
Used to explain the black-body radiation experiment.
The Quantum Story by Jim Baggott (2011) page 9 mentions that Planck apparently immediately recognized that Planck constant was a new fundamental physical constant, and could have potential applications in the definition of the system of units (TODO where was that published):
Planck wrote that the constants offered: 'the possibility of establishing units of length, mass, time and temperature which are independent of specific bodies or materials and which necessarily maintain their meaning for all time and for all civilizations, even those which are extraterrestrial and nonhuman, constants which therefore can be called "fundamental physical units of measurement".'
This was a visionary insight, and was finally realized in the 2019 redefinition of the SI base units.
Video 1.
Quantum Mechanics 2 - Photons by ViaScience (2012)
Source. Contains a good explanation of how discretization + energy increases with frequency explains the black-body radiation experiment curve: you need more and more energy for small wavelengths, each time higher above the average energy available.
Eukaryote without mitochondria Updated +Created
pubmed.ncbi.nlm.nih.gov/27185558/ A Eukaryote without a Mitochondrial Organelle by Karnkowska et. al (2016)
Energy-momentum relation Updated +Created
Emission theory (vision) Updated +Created
It is so mind blowing that people believed in this theory. How can you think that, when you turn on a lamp and then you see? Obviously, the lamp must be emitting something!!!
Then comes along this epic 2002 paper: pubmed.ncbi.nlm.nih.gov/12094435/ "Fundamentally misunderstanding visual perception. Adults' belief in visual emissions". TODO review methods...

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