Zermelo-Fraenkel set theory Updated 2025-10-14
One of the first formal proof systems. This is actually understandable!
This is Ciro Santilli-2020 definition of the foundation of mathematics (and the only one he had any patience to study at all).
TODO what are its limitations? Why were other systems created?
ELF Hello World Tutorial Generate the example Updated 2025-07-16
hello_world.asm
section .data
hello_world db "Hello world!", 10
hello_world_len equ $ - hello_world
section .text
global _start
_start:
mov rax, 1
mov rdi, 1
mov rsi, hello_world
mov rdx, hello_world_len
syscall
mov rax, 60
mov rdi, 0
syscallCompiled with:
nasm -w+all -f elf64 -o 'hello_world.o' 'hello_world.asm'
ld -o 'hello_world.out' 'hello_world.o' Yeast artificial chromosome Updated 2025-07-16
ELF Hello World Tutorial How to learn Updated 2025-07-16
Spin like mad between:
- standards
- high level generators. We use the assembler
asand linkerld. - hexdumps
- file decompilers. We use
readelf. It makes it faster to read the ELF file by turning it into human readable output. But you must have seen one byte-by-byte example first, and think howreadelfoutput maps to the standard. - low-level generators: stand-alone libraries that let you control every field of the ELF files you generated. github.com/BR903/ELFkickers, github.com/sqall01/ZwoELF and many more on GitHub.
- consumer: the
execsystem call of the Linux kernel can parse ELF files to starts processes: github.com/torvalds/linux/blob/v4.11/fs/binfmt_elf.c, stackoverflow.com/questions/8352535/how-does-kernel-get-an-executable-binary-file-running-under-linux/31394861#31394861
ELF Hello World Tutorial Index 0 section Updated 2025-07-16
Contained in bytes 0x40 to 0x7F.
The first section is always magic: www.sco.com/developers/gabi/2003-12-17/ch4.sheader.html says:
If the number of sections is greater than or equal to SHN_LORESERVE (0xff00), e_shnum has the value SHN_UNDEF (0) and the actual number of section header table entries is contained in the sh_size field of the section header at index 0 (otherwise, the sh_size member of the initial entry contains 0).
There are also other magic sections detailed in
Figure 4-7: Special Section Indexes. Skew-symmetric form Updated 2025-07-16
CAIDA/commoncrawl-host-ip-mapper Updated 2025-07-16
Human spinal cord Updated 2025-07-16
Particle in a box Updated 2025-07-16
Quantum tunnelling Updated 2025-07-16
Examples:
- flash memory uses quantum tunneling as the basis for setting and resetting bits
- alpha decay is understood as a quantum tunneling effect in the nucleus
Supercomputer by owner Updated 2025-07-16
Superfluid helium-4 Updated 2025-07-16
Also sometimes called helium II, in contrast to helium I, which is the non-superfluid liquid helium phase.
Superfluid helium Resonance Experiment by Dietterich Labs (2019)
Source. Hacker News Updated 2025-07-16
The most popular programming news sharing forum of the 2010's by far. If your content gets shared there, and it stays on top for a day, the traffic peak will be incredible. Reddit posts are sure to follow.
Ciro Santilli had a few of his content shared there as mentioned at the best articles by Ciro Articles.
Hadamard gate Updated 2025-07-16
The Hadamard gate takes or (quantum states with probability 1.0 of measuring either 0 or 1), and produces states that have equal probability of 0 or 1.
Equation 1.
Hadamard gate matrix
. 
Angry Video Game Nerd Updated 2025-07-16
www.youtube.com/watch?v=h6DtVHqyYts Big Rigs: Over the Road Racing (PC) (2014) is perhaps his best video.
Half-life Updated 2025-07-16
The half-life of radioactive decay, which as discovered a few years before quantum mechanics was discovered and matured, was a major mystery. Why do some nuclei fission in apparently random fashion, while others don't? How is the state of different nuclei different from one another? This is mentioned in Inward Bound by Abraham Pais (1988) Chapter 6.e Why a half-life?
The term also sees use in other areas, notably biology, where e.g. RNAs spontaneously decay as part of the cell's control system, see e.g. mentions in E. Coli Whole Cell Model by Covert Lab.
Hall effect Updated 2025-07-16
Hall effect experimental diagram
. Source. The Hall effect refers to the produced voltage , AKA on this setup.
An intuitive video is:
The key formula for it is:where:
- : current on x direction, which we can control by changing the voltage
- : strength of transversal magnetic field applied
- : charge carrier density, a property of the material used
- : height of the plate
- : electron charge
Applications:
- the direction of the effect proves that electric currents in common electrical conductors are made up of negative charged particles
- measure magnetic fields, TODO vs other methods
Other more precise non-classical versions:
Spin half Updated 2025-07-16
Leads to the Dirac equation.
Genome Project-Write Updated 2025-07-16
Hash function Updated 2025-07-16
Applications:
- hash map which is a O(1) amortized implementation of a map
- creating unbreakable chains of data, e.g. for Git commits or Bitcoin.
- storing passwords on a server in a way that if the password database is stolen, attackers can't reuse them on other websites where the user used the same password: security.blogoverflow.com/2013/09/about-secure-password-hashing/
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