RE (complexity) Updated 2025-07-16
R (complexity) Updated 2025-07-16
Set of all decision problems solvable by a Turing machine, i.e. that decide if a string belongs to a recursive language.
Undecidable problem Updated 2025-07-16
Or in other words: there is no Turing machine that always halts for every input with the yes/no output.
Every undecidable problem must obviously have an infinite number of "possibilities of stuff you can try": if there is only a finite number, then you can brute-force it.
Lists of undecidable problems.
Coolest ones besides the obvious boring halting problem:
Difference between recursive language and recursively enumerable language Updated 2025-07-16
Recursive set Updated 2025-07-16
Drug liberalization Updated 2025-07-16
Ciro Santilli supports full legalization of all drugs, because he feels that it would be better overall for the world to have cheaper drugs and more drug addicts, but way, way less organized crime.
These should be extremely controlled of course, with extremely high taxes that puts their price just below the current illegal market, and a complete ban on any positive advertising.
Ciro believes that maybe the government could even go as far as giving free drugs to drug addicts so they don't have to rob to get a fix.
This is notably considering that drug-led organized crime completely dominates and corrupts the politics of many production and trafficking zones, which are already generally poor fucked up places to start with:Ciro's experiences in Brazil such as mentioned at São Remo, the favela next to USP, although much less extreme than the above, also come to mind.
Drug traffic corrupts everything. It prevents development of honest people. It is a cancer, which we have failed time and time a gain to cure. The only cure is to accept the other less insidious of addiction.
Bad trip Updated 2025-07-16
Drug traffic Updated 2025-07-16
List of recreational drugs Updated 2025-07-16
555 timer IC Updated 2025-07-16
Pixel Updated 2025-07-16
Raspberry Pi Foundation project Updated 2025-07-16
Hardware random number generation Updated 2025-07-16
Radio transceiver Updated 2025-07-16
Radio receiver Updated 2025-07-16
As well put by Wikipedia, a radio receiver has to perform three functions on the signal from the antenna:
- filtering, so you can tune the station you care about. This filters based on the frequency of the carrier wave you want. I.e. you use a bandpass filter.
- amplification: otherwise you won't be able to hear anything if the emitter is too far away
- demodulation: this means decoding the signal based on whatever way it was encoded, notably e.g. AM/FM
Transmitter Updated 2025-07-16
Quran character Updated 2025-07-16
Quran passage Updated 2025-07-16
Continuous-variable quantum information Updated 2025-07-16
It is also possible to carry out quantum computing without qubits using processes with a continuous spectrum of measurement.
As of 2020, these approaches seem less developed/promising, but who knows.
Quantum advantage Updated 2025-07-16
Similar to quantum supremacy, but add the goal that the computation must be useful, i.e. make money or solve some open mathematical problem, Ciro Santilli's wife was quite excited about the possibility of finding some counter examples in number theory with quantum computers.
There are unlisted articles, also show them or only show them.