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๐Ÿ”— Proving something exists nonconstructively using probability.

๐Ÿ”— Mathematics

The probabilistic method is a nonconstructive method, primarily used in combinatorics and pioneered by Paul Erdล‘s, for proving the existence of a prescribed kind of mathematical object. It works by showing that if one randomly chooses objects from a specified class, the probability that the result is of the prescribed kind is strictly greater than zero. Although the proof uses probability, the final conclusion is determined for certain, without any possible error.

This method has now been applied to other areas of mathematics such as number theory, linear algebra, and real analysis, as well as in computer science (e.g. randomized rounding), and information theory.

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๐Ÿ”— A list of April Fools' Day RFCs

๐Ÿ”— Internet ๐Ÿ”— Internet culture ๐Ÿ”— Comedy

A Request for Comments (RFC), in the context of Internet governance, is a type of publication from the Internet Engineering Task Force (IETF) and the Internet Society (ISOC), usually describing methods, behaviors, research, or innovations applicable to the working of the Internet and Internet-connected systems.

Almost every April Fools' Day (1 April) since 1989, the Internet RFC Editor has published one or more humorous Request for Comments (RFC) documents, following in the path blazed by the June 1973 RFC 527 called ARPAWOCKY, a parody of Lewis Carroll's nonsense poem "Jabberwocky". The following list also includes humorous RFCs published on other dates.

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๐Ÿ”— Garden path sentence

๐Ÿ”— Linguistics ๐Ÿ”— Linguistics/Applied Linguistics

A garden-path sentence is a grammatically correct sentence that starts in such a way that a reader's most likely interpretation will be incorrect; the reader is lured into a parse that turns out to be a dead end or yields a clearly unintended meaning. "Garden path" refers to the saying "to be led down [or up] the garden path", meaning to be deceived, tricked, or seduced. In A Dictionary of Modern English Usage, Fowler describes such sentences as unwittingly laying a "false scent".

Such a sentence leads the reader toward a seemingly familiar meaning that is actually not the one intended. It is a special type of sentence that creates a momentarily ambiguous interpretation because it contains a word or phrase that can be interpreted in multiple ways, causing the reader to begin to believe that a phrase will mean one thing when in reality it means something else. When read, the sentence seems ungrammatical, makes almost no sense, and often requires rereading so that its meaning may be fully understood after careful parsing.

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๐Ÿ”— Clashes between web and X11 colors in the CSS color scheme

๐Ÿ”— Color ๐Ÿ”— Project-independent assessment

In computing, on the X Window System, X11 color names are represented in a simple text file, which maps certain strings to RGB color values. It was traditionally shipped with every X11 installation, hence the name, and is usually located in <X11root>/lib/X11/rgb.txt. The web colors list is descended from it but differs for certain color names.

Color names are not standardized by Xlib or the X11 protocol. The list does not show continuity either in selected color values or in color names, and some color triplets have multiple names. Despite this, graphic designers and others got used to them, making it practically impossible to introduce a different list. In earlier releases of X11 (prior to the introduction of Xcms), server implementors were encouraged to modify the RGB values in the reference color database to account for gamma correction.

As of X.Org Release 7.4 rgb.txt is no longer included in the roll up release, and the list is built directly into the server. The optional module xorg/app/rgb contains the stand-alone rgb.txt file.

The list first shipped with X10 release 3 (X10R3) on 7 June 1986, having been checked into RCS by Jim Gettys in 1985. The same list was in X11R1 on 18 September 1987. Approximately the full list as is available today shipped with X11R4 on 29 January 1989, with substantial additions by Paul Ravelling (who added colors based on Sinclair Paints samples), John C. Thomas (who added colors based on a set of 72 Crayola crayons he had on hand) and Jim Fulton (who reconciled contributions to produce the X11R4 list). The project was running DEC VT240 terminals at the time, so would have worked to that device.

In some applications multipart names are written with spaces, in others joined together, often in camel case. They are usually matched insensitive of case and the X Server source code contains spaced aliases for most entries; this article uses spaces and uppercase initials except where variants with spaces are not specified in the actual code.

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๐Ÿ”— Video game crash of 1983

๐Ÿ”— Video games ๐Ÿ”— Video games/Nintendo

The video game crash of 1983 (known as the Atari shock in Japan) was a large-scale recession in the video game industry that occurred from 1983 to 1985, primarily in the United States. The crash was attributed to several factors, including market saturation in the number of game consoles and available games, and waning interest in console games in favor of personal computers. Revenues peaked at around $3.2 billion in 1983, then fell to around $100 million by 1985 (a drop of almost 97 percent). The crash abruptly ended what is retrospectively considered the second generation of console video gaming in North America.

Lasting about two years, the crash shook the then-booming industry, and led to the bankruptcy of several companies producing home computers and video game consoles in the region. Analysts of the time expressed doubts about the long-term viability of video game consoles and software.

The North American video game console industry eventually recovered a few years later, mostly due to the widespread success of the Nintendo Entertainment System (NES) in 1985; Nintendo designed the NES as the Western branding for its Famicom console originally released in 1983 in order to avoid the missteps which caused the 1983 crash and avoid the stigma which video games had at that time.

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๐Ÿ”— Wine-dark sea

๐Ÿ”— Classical Greece and Rome

The wine-dark sea is a traditional English translation of ฮฟแผถฮฝฮฟฯˆ ฯ€ฯŒฮฝฯ„ฮฟฯ‚ (oรฎnops pรณntos, IPA: /รดiฬฏ.nops pรณn.tos/), from ฮฟแผถฮฝฮฟฯ‚ (oรฎnos, โ€œwineโ€) + แฝ„ฯˆ (รณps, โ€œeye; faceโ€). It is an epithet in Homer of uncertain meaning: a literal translation is "wine-face sea" (wine-faced, wine-eyed). It is attested five times in the Iliad and twelve times in the Odyssey, often to describe rough, stormy sea.

The only other use of oรฎnops in the works of Homer is for oxen (once in both his epic poems), where it seems to describe a reddish color, which has given rise to various speculations about what it could mean about either the state of Aegean Sea during antiquity or the color perception of Ancient Greeks.

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๐Ÿ”— Great Woman of Mathematics: Marie-Sophie Germain, 1776-1831

๐Ÿ”— Biography ๐Ÿ”— Mathematics ๐Ÿ”— France ๐Ÿ”— Women scientists ๐Ÿ”— Biography/science and academia ๐Ÿ”— Women's History ๐Ÿ”— Mathematics/Mathematicians

Marie-Sophie Germain (French:ย [maสi sษ”fi ส’ษ›สmษ›ฬƒ]; 1 April 1776 โ€“ 27 June 1831) was a French mathematician, physicist, and philosopher. Despite initial opposition from her parents and difficulties presented by society, she gained education from books in her father's library, including ones by Leonhard Euler, and from correspondence with famous mathematicians such as Lagrange, Legendre, and Gauss (under the pseudonym of ยซMonsieur LeBlancยป). One of the pioneers of elasticity theory, she won the grand prize from the Paris Academy of Sciences for her essay on the subject. Her work on Fermat's Last Theorem provided a foundation for mathematicians exploring the subject for hundreds of years after. Because of prejudice against her sex, she was unable to make a career out of mathematics, but she worked independently throughout her life. Before her death, Gauss had recommended that she be awarded an honorary degree, but that never occurred. On 27 June 1831, she died from breast cancer. At the centenary of her life, a street and a girlsโ€™ school were named after her. The Academy of Sciences established the Sophie Germain Prize in her honor.

๐Ÿ”— Volume of an n-ball tends to a limiting value of 0 as n goes to infinity

๐Ÿ”— Mathematics

In geometry, a ball is a region in a space comprising all points within a fixed distance, called the radius, from a given point; that is, it is the region enclosed by a sphere or hypersphere. An n-ball is a ball in an n-dimensional Euclidean space. The volume of a n-ball is the Lebesgue measure of this ball, which generalizes to any dimension the usual volume of a ball in 3-dimensional space. The volume of a n-ball of radius R is R n V n , {\displaystyle R^{n}V_{n},} where V n {\displaystyle V_{n}} is the volume of the unit n-ball, the n-ball of radius 1.

The real number V n {\displaystyle V_{n}} can be expressed by a expression involving the gamma function. It can be computed with several recurrence relations. It can be expressed in terms of A n , {\displaystyle A_{n},} the area of the unit n-sphere.

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๐Ÿ”— Anvil Firing

๐Ÿ”— Canada ๐Ÿ”— Appalachia ๐Ÿ”— Canada/British Columbia

Anvil firing (also known as anvil launching or anvil shooting) is the practice of firing an anvil into the air with gunpowder.

In the UK, the term refers to a method of testing anvils. Black powder was poured onto the top of the anvil and ignited. If the anvil did not shatter it was deemed safe to use.

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๐Ÿ”— Project Sanguine: a 6000 mile long antenna to communicate with submarines @ 76Hz

๐Ÿ”— Military history ๐Ÿ”— Military history/Military science, technology, and theory ๐Ÿ”— Military history/Maritime warfare

Project Sanguine was a U.S. Navy project, proposed in 1968 for communication with submerged submarines using extremely low frequency (ELF) radio waves. The originally proposed system, hardened to survive a nuclear attack, would have required a giant antenna covering two fifths of the state of Wisconsin. Because of protests and potential environmental impact, the proposed system was never implemented. A smaller, less hardened system called Project ELF consisting of two linked ELF transmitters located at Clam Lake, Wisconsin and Republic, Michigan was built beginning in 1982 and operated from 1989 until 2004. The system transmitted at a frequency of 76ย Hz. At ELF frequencies the bandwidth of the transmission is very small, so the system could only send short coded text messages at a very low data rate. These signals were used to summon specific vessels to the surface to receive longer operational orders by ordinary radio or satellite communication.