epsilon

Look up Ε or ε in Wiktionary, the free dictionary.

Greek alphabet
Αα	Alpha	Νν	Nu
Ββ	Beta	Ξξ	Xi
Γγ	Gamma	Οο	Omicron
Δδ	Delta	Ππ	Pi
Εε	Epsilon	Ρρ	Rho
Ζζ	Zeta	Σσς	Sigma
Ηη	Eta	Ττ	Tau
Θθ	Theta	Υυ	Upsilon
Ιι	Iota	Φφ	Phi
Κκ	Kappa	Χχ	Chi
Λλ	Lambda	Ψψ	Psi
Μμ	Mu	Ωω	Omega
Obsolete letters
	Digamma		Qoppa
	San		Sampi
Other characters
	Stigma		Sho
	Heta
Greek diacritics

Epsilon (uppercase Ε, lowercase ε; Greek: Έψιλον) is the fifth letter of the Greek alphabet, corresponding phonetically to a close-mid front unrounded vowel /e/. In the system of Greek numerals it has a value of 5. It was derived from the Phoenician letter He . Letters that arose from Epsilon include the Roman E and Cyrillic Ye.

"Epsilon" (ἒ ψιλόν, "simple e") was coined in the Middle Ages to distinguish the letter from the diphthong αι, which started being pronounced the same way during the period of New Testament Greek.

There are two common symbols used for the lowercase epsilon: the lunate epsilon ϵ and the minuscule open e symbol ɛ. The two are often used interchangeably (although a particular document should generally use one or the other consistently).

The lunate epsilon ϵ (\epsilon, , in LaTeX) has its origins in medieval Greek. The open e epsilon ɛ (\varepsilon, , in LaTeX), also called a Latin epsilon, derives from the extended Latin alphabet.

The lunate epsilon ϵ is not to be confused with the set membership symbol ∈, nor should the Latin ɛ be confused with the lunate Σ (Sigma).

Upper case: character code 0395 (or 494). Lower case: character code 03B5 (lunate) or 025B (Latin).

Symbol

The upper-case Epsilon is not commonly used outside of the Greek language because of its similarity to the Latin letter E.

The lower-case epsilon, ε/ϵ, or open e, ɛ, (see above) is used as the symbol for:

• In mathematics (particularly calculus), an arbitrarily small positive quantity is commonly denoted ε; see (ε, δ)-definition of limit.
• In mathematics, the Levi-Civita symbol.
• In mathematics, to represent the dual numbers: a + bε, with ε²=0 and ε≠0.
• In mathematics, sometimes used to denote the Heaviside step function.
• In set theory, the limit ordinal of the sequence .
• In computing, the precision of a numeric data type and floating-point machine epsilon.
• In computer science, the empty string, though different writers use a variety of other symbols for the empty string as well, including the lower case Greek letter lambda.
• In physics, the permittivity of a medium.
• In physics and electronics, the EMF of a circuit
• In physics, the strain of a material (a ratio of extensions).
• In automata theory, a transition that involves no shifting of an input symbol.
• In astronomy, the fifth-brightest star in a constellation (see Bayer designation).
• In the International Phonetic Alphabet, the open-mid front unrounded vowel (but generally written ɛ instead of ϵ), as in the English word "pet" (/pɛt/).
• In astronomy, Epsilon is the name for Uranus' most distant and most visible ring.
• In chemistry, the molar extinction coefficient of a chromophore.
• In economics, ε refers to elasticity.
• In statistics, to refer to error terms.
• In linguistics, the symbol for an open-mid front unrounded vowel.
• In agriculture, to represent the "photosynthetic efficiency" of a particular plant or crop.

Fictional names

• In the popular web series "Red vs. Blue", Epsilon is the name of Agent Washington's AI, posessing memories from the breaking of the Alpha AI by Project Frelancer.
• Epsilon in Malaysian Pale is the name of the second solo album released by Tangerine Dream leader Edgar Froese in 1975.
• Epsilon is also an Australian light-powered female-looking robot that fought Pluto in an episode of Astro Boy.
• Epsilon Eridani III is the planet that the spacestation Babylon 5 orbited in the eponymous sci-fi television series.
• E-104 Epsilon is also the name of a robot in Sonic Adventure.
• Epsilon is an otherworldy being in the book The Riddles of Epsilon by Christine Morton-Shaw.
• "Epsilon 9" is the name of the Federation space station consumed by the V'ger cloud in Star Trek: The Motion Picture.
• Epsilon is the name of an unlockable creature in the game Monster Rancher 2.
• In Greek it is used for Epsilon Team.
• "Epsilon Mirror" is the name of one of Aika's moves in the video game Skies of Arcadia.
• Epsilon is the leader of the Rebellion in Mega Man X: Command Mission.
• "The Epsilon Program" is a mysterious cult in the video game Grand Theft Auto: San Andreas by Game Developer Rockstar North. This cult is thought to be based on Scientology.
• The Epsilon Project is a fictional experiment mentioned in the Dreamcast and Xbox versions of Dead or Alive 2 and is based around cloning.
• Epsilon is the lowest of five social castes in the Aldous Huxley novel Brave New World.
• "Plan Epsilon" was one of many plans to restore Doctor Doom to life in the event of his death, as shown in Fantastic Four issue no. 246, written by Stan Lee.
• Epsilon-Eagle is the name of the protagonist in the Sega Mega Drive game Alien Soldier.
• Epsilon was the name given to one of the ground support teams in the Sony Playstation game G-Police.
• Epsilon is the name of the newly resurrected Yuri Faction in the Yuri's Revenge mod Mental Omega.
• Epsilon was one of the warriors of Asgard in the Anime series Saint Seiya, Fenrir Epsilon, The Northern Wolf, when Dragon Shiryu had to fight for his life against him on his way to rescue Hilda.
• Epsilon was the name of the chef dog in the Pixar movie Up when Carl and Russell are in Muntz's lair.

Other uses

• "Epsilon" is the name used by General Motors for the post-2003 Epsilon platform.
• EpsilonEuskadi carmaker ^[1] and EpsilonEuskadi LMP1 car.
• "Barazi Epsilon" a manufacturer in the 2009 Superleague Formula season for the Olympique Lyonnais car.
• Hurricane Epsilon, a storm of the 2005 Atlantic hurricane season.
• Epsilon TB-30 is a training aircraft made by Socata and used by the French, Portuguese, Senegalese and Togo airforces. Introduced in 1984 it provides basic and intermediate training, and has a 300 hp lycoming engine.
• Stars Epsilon Eridani and 40 Epsilon.

References

• Hoffman, Paul; The man who loved only numbers. Hyperion, 1998. ISBN 0-7868-6362-5.

1. ^ EPSILON EUSKADI==JOAN VILLADELPRAT & SERGIO RINLAND & JORDI CATON==AZKOITIA (43º 10' 22" N - 2º 19' 26" O)