Void type

The void type, in several programming languages derived from C and Algol68, is the type for the result of a function that returns normally, but does not provide a result value to its caller. Usually such functions are called for their side effects, such as performing some task or writing to their output parameters. The usage of the void type in such context is comparable to that of the syntactic constructs which define subroutines in Visual Basic and procedures in Pascal. It is also similar to the unit type used in functional programming languages and type theory; however, there are some differences in allowable usage, in that the void type is taken to be an empty type with no values. See Unit type#In programming languages for a comparison.

C and C++ also support the pointer to void type (specified as void *), but this is an unrelated notion. Variables of this type are pointers to data of an unspecified type, so in this context (but not the others) void * acts as a universal or top type. A program can probably convert a pointer to any type of data (except a function pointer) to a pointer to void and back to the original type without losing information, which makes these pointers useful for polymorphic functions. The C language standard does not guarantee that the different pointer types have the same size.

Aether (classical element)

According to ancient and medieval science, aether (Greek: αἰθήρ aithēr), also spelled æther or ether, also called quintessence, is the material that fills the region of the universe above the terrestrial sphere. The concept of aether was used in several theories to explain several natural phenomena, such as the traveling of light and gravity. In the late 19th century, physicists postulated that aether permeated all throughout space, providing a medium through which light could travel in a vacuum, but evidence for the presence of such a medium was not found in the Michelson–Morley experiment.

Mythological origins

The word αἰθήρ (aithēr) in Homeric Greek means "pure, fresh air" or "clear sky". In Greek mythology, it was thought to be the pure essence that the gods breathed, filling the space where they lived, analogous to the air breathed by mortals. It is also personified as a deity, Aether, the son of Erebus and Nyx in traditional Greek mythology. Aether is related to αἴθω "to incinerate", and intransitive "to burn, to shine" (related is the name Aithiopes (Ethiopians; see Aethiopia), meaning "people with a burnt (black) visage"). See also Empyrean.

Void (band)

Void was a Washington D.C.-based hardcore punk/crossover thrash band. They were one of the first hardcore bands popular in the D.C. scene that was from outside the Beltway, hailing from Columbia, Maryland, a suburb located between D.C. and Baltimore.

History

The band formed in 1980 with lead singer John Weiffenbach, guitarist Jon "Bubba" Dupree, bassist Chris Stover, and drummer Sean Finnegan. They immediately acquired a cult following, in part due to Bubba Dupree's chaotic guitar style, wild performances, and John Weiffenbach's violent lyrics and frenzied behavior. In November 1981, they cut a demo tape at Inner Ear Studios which was produced by Alec MacKaye of The Faith, with whom they would share a split. They were soon picked up by Ian MacKaye and Jeff Nelson's label Dischord Records. In February 1982, they made their vinyl debut on Dischord with three songs on the Flex Your Head compilation. That spring, they went into the studio to cut twelve songs that were released in September 1982 as half of the Faith/Void split album released by Dischord Records.

NaNa (band)

NaNa is a Japanese musical duo from Tokyo, Japan, consisting of Chikako Watanabe and Shigeo Tamaru. Their music draws on several influences including alternative rock, experimental rock, trip hop and downtempo.

History

Chikako Watanabe (vocal) and Shigeo Tamaru (guitar/producer) came together to form NaNa in 1996. NaNa's chief goal was to create high quality demo tapes that would showcase their music to the world market. In the summer of 1997, NaNa got an offer from Ryuichi Sakamoto to be on his Radio show, and they appeared on the program. This led NaNa into their debut from Sakamoto's label. NaNa's first EP topped the Indies chart including Tower Records in Tokyo. Afterward they released two albums and four EP from Gut/Forlife label and Warner Music Japan. In 2007, they started digital distribution on iTunes and Amazon. Then they have since increased the number of the listeners little by little in different countries. Starting in 2007, NaNa's tracks have gradually received air-play primarily in the UK and the US. As of 2010, their music came to be listened to all over the world via local and Satellite Radio, and BBC regardless of the type of Radio station. In 2011, NaNa was ranked on the Billboard Magazine's (USA) charts. They spent 13 weeks from February 2011 on the Billboard Uncharted, climbed to the 12th place. In December 2011, they ranked No. 41 place on the Billboard's "The Best of 2011" (Year-End Chart, USA).

Type (designation)

The word Type followed by a number is a common way to name a weapon or product in a production series, similar in meaning to "Mark". "Type" was used extensively by the Japanese and Chinese militaries beginning in the 1920s, and is still in current use by the militaries of both nations. The United Kingdom uses a type number system for much of their military equipment. Many other nations use the word "Type" to designate products in a series.

Japan

The Imperial Japanese Navy (IJN) began using the Type-Number System in 1921 to designate aircraft accepted for production. The numbers used after the word "Type" were based on the number of years that the Emperor Taishō had reigned. Since his reign began in 1912, an aircraft ordered into production in 1921 would have been called "Type 10", the tenth year of the emperor's reign. At the end of 1926, the emperor died, leaving his son Hirohito as the Emperor Shōwa, and the numbering system was reset to mark the new emperor's reign.

In 1929, the government of Japan adopted a new system based on the imperial year. Aircraft ordered for production from 1929 onward were assigned the last two digits of the year marking the continuity of Japanese emperors. 1929 was the 2589th imperial year, so aircraft ordered that year were designated "Type 89". 1940 was the 2600th year, and the IJN numbering system was reset to single digits. New aircraft were designated 0 (zero). The well-known Mitsubishi A6M Zero was ordered into production in 1940 as the IJN "Type 0 Carrier Fighter" (Rei shiki Kanjō sentōki, 零式艦上戦闘機), and was popularly called the "Zero" because of its type.

Glossary of numismatics

This article is a collection of Numismatic and coin collecting terms with concise explanation for the beginner or professional.

Numismatics (ancient Greek: νομισματική) is the scientific study of money and its history in all its varied forms. While numismatists are often characterized as studying coins, the discipline also includes the study of banknotes, stock certificates, medals, medallions, and tokens (also referred to as Exonumia).

Sub-fields or related fields of numismatics are:

A

B

C

D

E

F

G

H

I

K

L

M

N

O

P

Q

R

S

T

U

V

Y

Z

References

Type theory

In mathematics, logic, and computer science, a type theory is any of a class of formal systems, some of which can serve as alternatives to set theory as a foundation for all mathematics. In type theory, every "term" has a "type" and operations are restricted to terms of a certain type.

Type theory is closely related to (and in some cases overlaps with) type systems, which are a programming language feature used to reduce bugs. The types of type theory were created to avoid paradoxes in a variety of formal logics and rewrite systems and sometimes "type theory" is used to refer to this broader application.

Two well-known type theories that can serve as mathematical foundations are Alonzo Church's typed λ-calculus and Per Martin-Löf's intuitionistic type theory.

History

The types of type theory were invented by Bertrand Russell in response to his discovery that Gottlob Frege's version of naive set theory was afflicted with Russell's paradox. This theory of types features prominently in Whitehead and Russell's Principia Mathematica. It avoids Russell's paradox by first creating a hierarchy of types, then assigning each mathematical (and possibly other) entity to a type. Objects of a given type are built exclusively from objects of preceding types (those lower in the hierarchy), thus preventing loops.