Mu (letter)


Mu is the 12th letter of the Greek alphabet, representing the voiced bilabial nasal. In the system of Greek numerals it has a value of 40. Mu was derived from the Egyptian hieroglyphic symbol for water, which had been simplified by the Phoenicians and named after their word for water, to become ? . Letters that derive from mu include the Roman M and the Cyrillic М, though the lowercase resembles a small Latin U.

Names

Ancient Greek

In Greek, the name of the letter was written μῦ and pronounced.

Modern Greek

In Modern Greek, the letter is spelled μι and pronounced. In polytonic orthography, it is written with an acute accent: μί.

Use as symbol

The lowercase letter mu is used as a special symbol in many academic fields. Uppercase mu is not used, because it appears identical to Latin M.

Prefix for units of measurement

"μ" is used as a unit prefix denoting a factor of 10−6, in this context, the symbol's name is "micro".
"μ" is conventionally used to denote certain things; however, any Greek letter or other symbol may be used freely as a variable name.
In classical physics and engineering:
In particle physics:
In thermodynamics:
In evolutionary algorithms:
  • μ, population size from which in each generation λ offspring will generate
In type theory:
  • Used to introduce a recursive data type. For example, is the type of lists with elements of type : a sum of unit, representing, with a pair of a and another . In this notation, is a binding form, where the variable introduced by is bound within the following term to the term itself. Via substitution and arithmetic, the type expands to, an infinite sum of ever-increasing products of . Another way to express the same type is.

    Chemistry

In chemistry:
In biology:
In pharmacology:
In orbital mechanics:
  • Standard gravitational parameter of a celestial body, the product of the gravitational constant G and the mass M
  • planetary discriminant, represents an experimental measure of the actual degree of cleanliness of the orbital zone, a criterion for defining a planet. The value of μ is calculated by dividing the mass of the candidate body by the total mass of the other objects that share its orbital zone.

    Music

  • Mu chord
  • Electronic musician Mike Paradinas runs the label Planet Mu which utilizes the letter as its logo, and releases music under the pseudonym μ-Ziq, pronounced "music"
  • Used as the name of the school idol group μ's, pronounced "muse", consisting of nine singing idols in the anime Love Live! School Idol Project
  • Official fandom name of Kpop group f, appearing as either MeU or 'μ'
  • Hip-hop artist Muonboy has taken inspiration from the particle for his stage name and his first EP named Mu uses the letter as its title.

    Cameras

The Olympus Corporation manufactures a series of digital cameras called Olympus μ .

Linguistics

In phonology:
In syntax:
  • μP can be used as the name for a functional projection.
In Celtic linguistics:
  • /μ/ can represent an Old Irish nasalized labial fricative of uncertain articulation, the ancestor of the sound represented by Modern Irish mh.

    Unicode

The lowercase mu appeared at in the 8-bit ISO-8859-1 encoding, from which Unicode and many other encodings inherited it. It was also at in the popular CP437 on the IBM PC. Unicode designates mu as is the compatibility equivalent of the micro sign.
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