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🔗 Computer science 🔗 Mathematics

In computational complexity theory, the unique games conjecture (often referred to as UGC) is a conjecture made by Subhash Khot in 2002. The conjecture postulates that the problem of determining the approximate value of a certain type of game, known as a unique game, has NP-hard computational complexity. It has broad applications in the theory of hardness of approximation. If the unique games conjecture is true and P ≠ NP, then for many important problems it is not only impossible to get an exact solution in polynomial time (as postulated by the P versus NP problem), but also impossible to get a good polynomial-time approximation. The problems for which such an inapproximability result would hold include constraint satisfaction problems, which crop up in a wide variety of disciplines.

The conjecture is unusual in that the academic world seems about evenly divided on whether it is true or not.

🔗 United States 🔗 History 🔗 Philosophy 🔗 Philosophy/Social and political philosophy 🔗 British Empire 🔗 Sociology 🔗 United States History 🔗 United States/U.S. history

The Strauss–Howe generational theory, also known as the Fourth Turning theory or simply the Fourth Turning, which was created by authors William Strauss and Neil Howe, describes a theorized recurring generation cycle in American history. According to the theory, historical events are associated with recurring generational personas (archetypes). Each generational persona unleashes a new era (called a turning) lasting around 20–22 years, in which a new social, political, and economic climate exists. They are part of a larger cyclical "saeculum" (a long human life, which usually spans between 80 and 90 years, although some saecula have lasted longer). The theory states that after every saeculum, a crisis recurs in American history, which is followed by a recovery (high). During this recovery, institutions and communitarian values are strong. Ultimately, succeeding generational archetypes attack and weaken institutions in the name of autonomy and individualism, which ultimately creates a tumultuous political environment that ripens conditions for another crisis.

Strauss and Howe laid the groundwork for their theory in their 1991 book Generations, which discusses the history of the United States as a series of generational biographies going back to 1584. In their 1997 book The Fourth Turning, the authors expanded the theory to focus on a fourfold cycle of generational types and recurring mood eras to describe the history of the United States, including the Thirteen Colonies and their British antecedents. However, the authors have also examined generational trends elsewhere in the world and described similar cycles in several developed countries.

Academic response to the theory has been mixed—some applauding Strauss and Howe for their "bold and imaginative thesis" and others criticizing the theory as being overly-deterministic, non-falsifiable, and unsupported by rigorous evidence, "about as scientific as astrology or a Nostradamus text." Strauss–Howe generational theory has also been described by some historians and journalists as a "pseudoscience" "kooky", and "an elaborate historical horoscope that will never withstand scholarly scrutiny."

Academic criticism has focused on the lack of rigorous empirical evidence for their claims, and the authors' view that generational groupings are far more powerful than other social groupings such as economic class, race, sex, religion and political parties.

WikiReader was a project to deliver an offline, text-only version of Wikipedia on a mobile device. The project was sponsored by Openmoko and made by Pandigital, and its source code has been released.

The project debuted an offline portable reader for Wikipedia in October 2009. Updates in multiple languages were available online and a twice-yearly offline update service delivered via Micro SD card was also available at a cost of $29 per year. WikiReader versions of the English Wikipedia, Wikiquote, Wiktionary and Project Gutenberg can be installed together on a user-supplied 16 GB Micro SDHC memory card. Unlike Wikipedia itself, the device features parental controls.

The device can also run programs written in the Forth programming language; a simple calculator program is included.

In late 2014, the WikiReader website and project itself were shut down and abandoned for unknown reasons. Existing WikiReaders no longer receive updates to their database. Devices, professionally produced updates, and homegrown updates continue to be available from the secondary markets (e.g. eBay and Amazon), as well as from community efforts centered around the WikiReader subreddit.

🔗 Disaster management 🔗 Africa 🔗 Greece 🔗 Turkey 🔗 Bulgaria 🔗 Africa/Libya 🔗 Weather 🔗 Weather/Non-tropical storms 🔗 Weather/Floods 🔗 Weather/Weather 🔗 Africa/Egypt 🔗 Weather/Tropical cyclones

Storm Daniel, also known as Cyclone Daniel, was the deadliest Mediterranean tropical-like cyclone ever recorded as well as the deadliest weather event during 2023. It caused catastrophic damage in Libya and also affected parts of southeastern Europe. Forming as a low-pressure system around 4 September 2023, the storm affected Greece, Bulgaria and also Turkey with extensive flooding. The storm then organized as a Mediterranean Low and was designated as Storm Daniel, in which it soon acquired quasi-tropical characteristics (TLC) and moved toward the coast of Libya, where it caused catastrophic flooding before degenerating into a remnant low. The storm was the result of an Omega block, as a high-pressure zone became sandwiched between two zones of low pressure, the isobars shaping a Greek letter Ω.

🔗 Economics 🔗 Law

The Brussels effect is the process of unilateral regulatory globalisation caused by the European Union de facto (but not necessarily de jure) externalising its laws outside its borders through market mechanisms.

🔗 Statistics

The Erlang distribution is a two-parameter family of continuous probability distributions with support ${\displaystyle x\in [0,\infty )}$. The two parameters are:

• a positive integer ${\displaystyle k,}$ the "shape", and
• a positive real number ${\displaystyle \lambda ,}$ the "rate". The "scale", ${\displaystyle \mu ,}$ the reciprocal of the rate, is sometimes used instead.

The Erlang distribution with shape parameter ${\displaystyle k=1}$ simplifies to the exponential distribution. It is a special case of the gamma distribution. It is the distribution of a sum of ${\displaystyle k}$ independent exponential variables with mean ${\displaystyle 1/\lambda }$ each.

The Erlang distribution was developed by A. K. Erlang to examine the number of telephone calls which might be made at the same time to the operators of the switching stations. This work on telephone traffic engineering has been expanded to consider waiting times in queueing systems in general. The distribution is also used in the field of stochastic processes.

🔗 Cryptography 🔗 Cryptography/Computer science

In cryptography, a zero-knowledge proof or zero-knowledge protocol is a method by which one party (the prover) can prove to another party (the verifier) that they know a value x, without conveying any information apart from the fact that they know the value x. The essence of zero-knowledge proofs is that it is trivial to prove that one possesses knowledge of certain information by simply revealing it; the challenge is to prove such possession without revealing the information itself or any additional information.

If proving a statement requires that the prover possesses some secret information, then the verifier will not be able to prove the statement to anyone else without possessing the secret information. The statement being proved must include the assertion that the prover has such knowledge, but not the knowledge itself. Otherwise, the statement would not be proved in zero-knowledge because it provides the verifier with additional information about the statement by the end of the protocol. A zero-knowledge proof of knowledge is a special case when the statement consists only of the fact that the prover possesses the secret information.

Interactive zero-knowledge proofs require interaction between the individual (or computer system) proving their knowledge and the individual validating the proof.

A protocol implementing zero-knowledge proofs of knowledge must necessarily require interactive input from the verifier. This interactive input is usually in the form of one or more challenges such that the responses from the prover will convince the verifier if and only if the statement is true, i.e., if the prover does possess the claimed knowledge. If this were not the case, the verifier could record the execution of the protocol and replay it to convince someone else that they possess the secret information. The new party's acceptance is either justified since the replayer does possess the information (which implies that the protocol leaked information, and thus, is not proved in zero-knowledge), or the acceptance is spurious, i.e., was accepted from someone who does not actually possess the information.

Some forms of non-interactive zero-knowledge proofs exist, but the validity of the proof relies on computational assumptions (typically the assumptions of an ideal cryptographic hash function).

🔗 Linguistics 🔗 Linguistics/Etymology

OK (spelling variations include okay, O.K., and ok) is an English word (originally American English) denoting approval, acceptance, agreement, assent, acknowledgment, or a sign of indifference. OK is frequently used as a loanword in other languages. It has been described as the most frequently spoken or written word on the planet. The origins of the word are disputed.

As an adjective, OK principally means "adequate" or "acceptable" as a contrast to "bad" ("The boss approved this, so it is OK to send out"); it can also mean "mediocre" when used in contrast with "good" ("The french fries were great, but the burger was just OK"). It fulfills a similar role as an adverb ("Wow, you did OK for your first time skiing!"). As an interjection, it can denote compliance ("OK, I will do that"), or agreement ("OK, that is fine"). It can mean "assent" when it is used as a noun ("the boss gave her the OK to the purchase") or, more colloquially, as a verb ("the boss OKed the purchase"). OK, as an adjective, can express acknowledgement without approval. As a versatile discourse marker or back-channeling item, it can also be used with appropriate intonation to show doubt or to seek confirmation ("OK?", "Is that OK?").

🔗 Languages

The Dolgopolsky list is a word list compiled by Aharon Dolgopolsky in 1964. It lists the 15 lexical items that have the most semantic stability, i.e. they are the 15 words least likely to be replaced by other words as a language evolves. It was based on a study of 140 languages from across Eurasia.

The words, with the first being the most stable, are:

1. I/me
2. two/pair
3. you (singular, informal)
4. who/what
5. tongue
6. name
7. eye
8. heart
9. tooth
10. no/not
11. nail (finger-nail)
12. louse/nit
13. tear/teardrop
14. water
15. dead

The first item in the list, I/me, has been replaced in none of the 140 languages during their recorded history; the fifteenth, dead, has been replaced in 25% of the languages.

The twelfth item, louse/nit, is well kept in the North Caucasian languages, Dravidian and Turkic, but not in other proto-languages.