Lambda
Greek alphabet  



History  
Use in other languages  
Related topics  
Lambda (/ˈlæmdə/;^{[1]} uppercase Λ, lowercase λ; Greek: λάμ(β)δα, lám(b)da) is the 11th letter of the Greek alphabet, representing the voiced alveolar lateral approximant IPA: [l]. In the system of Greek numerals, lambda has a value of 30. Lambda is derived from the Phoenician Lamed . Lambda gave rise to the Latin L and the Cyrillic El (Л). The ancient grammarians and dramatists give evidence to the pronunciation as [laːbdaː] (λάβδα) in Classical Greek times.^{[2]} In Modern Greek, the name of the letter, Λάμδα, is pronounced [ˈlam.ða].
In early Greek alphabets, the shape and orientation of lambda varied.^{[3]} Most variants consisted of two straight strokes, one longer than the other, connected at their ends. The angle might be in the upperleft, lowerleft ("Western" alphabets) or top ("Eastern" alphabets). Other variants had a vertical line with a horizontal or sloped stroke running to the right. With the general adoption of the Ionic alphabet, Greek settled on an angle at the top; the Romans put the angle at the lowerleft.
The HTML 4 character entity references for the Greek capital and small letter lambda are Λ
and λ
respectively.^{[4]} The Unicode code points for lambda are U+039B and U+03BB.
Symbol[edit]
Uppercase letter Λ[edit]
This section has multiple issues. Please help improve it or discuss these issues on the talk page. (Learn how and when to remove these template messages)

Examples of the symbolic use of uppercase lambda include:
 The lambda particle is a type of subatomic particle in subatomic particle physics.
 Lambda is the set of logical axioms in the axiomatic method of logical deduction in firstorder logic.
 There is a poetical allusion to the use of Lambda as a shield blazon by the Spartans.^{[citation needed]}^{[5]}
 Lambda is the von Mangoldt function in mathematical number theory.
 Lambda denotes the de Bruijn–Newman constant which is closely connected with Riemann's hypothesis.
 In statistics, lambda is used for the likelihood ratio.
 In statistics, Wilks's lambda is used in multivariate analysis of variance (MANOVA analysis) to compare group means on a combination of dependent variables.
 In the spectral decomposition of matrices, lambda indicates the diagonal matrix of the eigenvalues of the matrix.
 In computer science, lambda is the time window over which a process is observed for determining the working memory set for a digital computer's virtual memory management.
 In astrophysics, lambda represents the likelihood that a small body will encounter a planet or a dwarf planet leading to a deflection of a significant magnitude. An object with a large value of lambda is expected to have cleared its neighbourhood, satisfying the current definition of a planet.
 In crystal optics, lambda is used to represent a lattice period.
 In NATO military operations, a chevron (a heraldic symbol which looks like a capital letter lambda or inverted V) is painted on the vehicles of this military alliance for identification.
 In electrochemistry, lambda denotes the "equivalent conductance" of an electrolyte solution.
 In cosmology, lambda is the symbol for the cosmological constant, a term added to some dynamical equations to account for the accelerating expansion of the universe.
 In optics, lambda denotes the grating pitch of a Bragg reflector. Also in optics, it denotes wavelength of light.
 In politics, the lambda is the symbol of Identitarianism, a white nationalist movement that originated in France before spreading out to the rest of Europe and later on to North America, Australia and New Zealand. The Identitarian lambda represents the Battle of Thermopylae.
Lowercase letter λ[edit]
This section has multiple issues. Please help improve it or discuss these issues on the talk page. (Learn how and when to remove these template messages)

Examples of the symbolic use of lowercase lambda include:
 Lambda indicates the wavelength of any wave, especially in physics, electronic engineering, and mathematics.^{[6]}
 In evolutionary algorithms, λ indicates the number of offspring that would be generated from μ current population in each generation. The terms μ and λ are originated from Evolution strategy notation.
 Lambda indicates the radioactivity decay constant in nuclear physics and radioactivity. This constant is very simply related (by a multiplicative constant) to the halflife of any radioactive material.
 In probability theory, lambda represents the density of occurrences within a time interval, as modelled by the Poisson distribution.
 In mathematical logic and computer science, lambda is used to introduce anonymous functions expressed with the concepts of lambda calculus.
 Lambda indicates an eigenvalue in the mathematics of linear algebra.
 In the physics of electric fields, lambda sometimes indicates the linear charge density of a uniform line of electric charge (measured in coulombs per meter).
 Lambda denotes a Lagrange multiplier in multidimensional calculus.
 In solidstate electronics, lambda indicates the channel length modulation parameter of a MOSFET.
 In ecology, lambda denotes the longterm intrinsic growth rate of a population. This value is often calculated as the dominant eigenvalue of the age/size class matrix.
 In formal language theory and in computer science, lambda denotes the empty string.
 Lambda is a nonstandard symbol in the International Phonetic Alphabet for the voiced alveolar lateral affricate [dɮ].
 Lambda denotes the Lebesgue measure in mathematical set theory.
 The Goodman and Kruskal's lambda in statistics indicates the proportional reduction in error when one variable's values are used to predict the values of another variable.
 Lambda denotes the oxygen sensor in a vehicle that measures the airtofuel ratio in the exhaust gases of an internalcombustion engine.
 A Lambda 4S solidfuel rocket was used to launch Japan's first orbital satellite in 1970.^{[7]}
 Lambda denotes the failure rate of devices and systems in reliability theory, and it is measured in failure events per hour. Numerically, this lambda is also the reciprocal of the mean time between failures.
 In criminology, lambda denotes an individual's frequency of offences.
 In electrochemistry, lambda also denotes the ionic conductance of a given ion (the composition of the ion is generally shown as a subscript to the lambda character).
 In neurobiology, lambda denotes the length constant (or exponential rate of decay) of the electric potential across the cell membrane along a length of a nerve cell's axon.
 In the science and technology of heat transfer, lambda denotes the heat of vaporization per mole of material (a.k.a. its "latent heat").^{[8]}
 In the technology and science of celestial navigation, lambda denotes the longitude as opposed to the Roman letter "L", which denotes the latitude.
 A block style lambda is used as a recurring symbol in the Valve computer game series HalfLife,^{[9]} referring to the Lambda Complex of the fictional Black Mesa Research Facility, as well as making appearances in the sequel HalfLife 2, and its subsequent prequel HalfLife: Alyx as an in universe symbol of resistance.^{[10]}
 In 1970, a lowercase lambda was chosen by Tom Doerr as the symbol of the New York chapter of the Gay Activists Alliance.^{[11]}^{[12]} The lambda symbol became associated with Gay Liberation^{[13]}^{[14]} and recognized as an LGBT symbol for some time afterwards, being used as such by the International Gay Rights Congress in Edinburgh.^{[15]}
Litra symbol[edit]
The Roman libra and Byzantine lítra (λίτρα), which served as both the pound mass unit and liter volume unit, were abbreviated in Greek using lambda with modified forms of the iota subscript (as λͅ). These are variously encoded in Unicode. The Ancient Greek Numbers Unicode block includes 10183 GREEK LITRA SIGN (𐆃) as well as 𐅢, which is described as 10162 GREEK ACROPHONIC HERMIONIAN TEN^{[16]} but was much more common as a form of the litra sign. A variant of the sign can be formed from 0338 COMBINING LONG SOLIDUS OVERLAY and either 039B GREEK CAPITAL LETTER LAMDA (Λ̸) or 03BB GREEK SMALL LETTER LAMDA (λ̸).^{[17]}
Character encodings[edit]
Unicode uses the (Modern Greekbased) spelling "lamda" in character names, instead of "lambda", due to "the preexisting names in ISO 88597, as well as preferences expressed by the Greek National Body".^{[18]}
 Greek Lambda / Coptic Laula
Preview  Λ  λ  ᴧ  Ⲗ  ⲗ  

Unicode name  GREEK CAPITAL LETTER LAMDA  GREEK SMALL LETTER LAMDA  GREEK LETTER SMALL CAPITAL LAMDA  COPTIC CAPITAL LETTER LAULA  COPTIC SMALL LETTER LAULA  
Encodings  decimal  hex  dec  hex  dec  hex  dec  hex  dec  hex 
Unicode  923  U+039B  955  U+03BB  7463  U+1D27  11414  U+2C96  11415  U+2C97 
UTF8  206 155  CE 9B  206 187  CE BB  225 180 167  E1 B4 A7  226 178 150  E2 B2 96  226 178 151  E2 B2 97 
Numeric character reference  Λ 
Λ 
λ 
λ 
ᴧ 
ᴧ 
Ⲗ 
Ⲗ 
ⲗ 
ⲗ 
Named character reference  Λ  λ  
DOS Greek  138  8A  162  A2  
DOS Greek2  182  B6  229  E5  
Windows1253  203  CB  235  EB  
TeX  \Lambda  \lambda 
 Mathematical Lambda
Preview  𝚲  𝛌  𝛬  𝜆  𝜦  𝝀  

Unicode name  MATHEMATICAL BOLD CAPITAL LAMDA 
MATHEMATICAL BOLD SMALL LAMDA 
MATHEMATICAL ITALIC CAPITAL LAMDA 
MATHEMATICAL ITALIC SMALL LAMDA 
MATHEMATICAL BOLD ITALIC CAPITAL LAMDA 
MATHEMATICAL BOLD ITALIC SMALL LAMDA  
Encodings  decimal  hex  dec  hex  dec  hex  dec  hex  dec  hex  dec  hex 
Unicode  120498  U+1D6B2  120524  U+1D6CC  120556  U+1D6EC  120582  U+1D706  120614  U+1D726  120640  U+1D740 
UTF8  240 157 154 178  F0 9D 9A B2  240 157 155 140  F0 9D 9B 8C  240 157 155 172  F0 9D 9B AC  240 157 156 134  F0 9D 9C 86  240 157 156 166  F0 9D 9C A6  240 157 157 128  F0 9D 9D 80 
UTF16  55349 57010  D835 DEB2  55349 57036  D835 DECC  55349 57068  D835 DEEC  55349 57094  D835 DF06  55349 57126  D835 DF26  55349 57152  D835 DF40 
Numeric character reference  𝚲 
𝚲 
𝛌 
𝛌 
𝛬 
𝛬 
𝜆 
𝜆 
𝜦 
𝜦 
𝝀 
𝝀 
Preview  𝝠  𝝺  𝞚  𝞴  

Unicode name  MATHEMATICAL SANSSERIF BOLD CAPITAL LAMDA 
MATHEMATICAL SANSSERIF BOLD SMALL LAMDA 
MATHEMATICAL SANSSERIF BOLD ITALIC CAPITAL LAMDA 
MATHEMATICAL SANSSERIF BOLD ITALIC SMALL LAMDA  
Encodings  decimal  hex  dec  hex  dec  hex  dec  hex 
Unicode  120672  U+1D760  120698  U+1D77A  120730  U+1D79A  120756  U+1D7B4 
UTF8  240 157 157 160  F0 9D 9D A0  240 157 157 186  F0 9D 9D BA  240 157 158 154  F0 9D 9E 9A  240 157 158 180  F0 9D 9E B4 
UTF16  55349 57184  D835 DF60  55349 57210  D835 DF7A  55349 57242  D835 DF9A  55349 57268  D835 DFB4 
Numeric character reference  𝝠 
𝝠 
𝝺 
𝝺 
𝞚 
𝞚 
𝞴 
𝞴 
These characters are used only as mathematical symbols. Stylized Greek text should be encoded using the normal Greek letters, with markup and formatting to indicate text style.
See also[edit]
 Barred lambda  ƛ
 El (Cyrillic) – Л, л
 Fraser alphabet#Consonants
 Greek letters used in mathematics, science, and engineering
References[edit]
 ^ "lambda". Oxford English Dictionary (Online ed.). Oxford University Press. (Subscription or participating institution membership required.)
 ^ Herbert Weir Smyth. A Greek Grammar for Colleges. I.1.c
 ^ "Epigraphic Sources for Early Greek Writing". Poinikastas.CSAD.ox.ac.uk. Retrieved 20111003.
 ^ "HTML 4.01 Specification. 24. Character entity references in HTML 4". World Wide Web Consortium.
 ^ Philodemus (2003). On Poems. Oxford University Press. p. 212. ISBN 9780199262854.
 ^ Nelkon, Michael (1977). Fundamentals of Physics. St. Albans, Hertfordshire: HartDavis Educational. p. 329.
 ^ "Encyclopedia Astronautica: Lambda". Astronautix.com. Archived from the original on 20121022. Retrieved 20121218.
 ^ Wankat Separation Process Engineering 2nd ed, Prentice Hall
 ^ "HalfLife on Steam". store.steampowered.com. Valve. Retrieved 20170102.
 ^ "HalfLife 2 on Steam". store.steampowered.com. Valve. Retrieved 20170102.
 ^ Rapp, Linda (2004). "Gay Activists Alliance" (PDF). glbtq.com.
 ^ "1969, The Year of Gay Liberation". The New York Public Library. June 2009. Retrieved 17 November 2018.
 ^ Goodwin, Joseph P. (1989). "It Takes One to Know One". More Man Than You'll Ever Be: Gay Folklore and Acculturation in Middle America. Indiana University Press. p. 26. ISBN 9780253338938.
 ^ Rapp, Linda (2003). "Symbols" (PDF). glbtq.com.
 ^ Haggerty, George E., ed. (2000). Gay Histories and Cultures: An Encyclopedia (Encyclopedia of Gay Histories and Cultures, Volume II) (1 ed.). London: Garland Publishing. p. 529. ISBN 0815318804. OCLC 750790369.
 ^ Unicode Ancient Greek Numbers block.
 ^ "Thesaurus Linguae Graecae" (PDF). Stephanus.TLG.UCI.edu. Archived from the original (PDF) on 20110716.
 ^ "Unicode Mail List Archive: RE: Greek letter "LAMDA"?".