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Greek letters are used in mathematics, science, engineering, and other areas where mathematical notation is used as symbols for constants, special functions, and also conventionally for variables representing certain quantities. In these contexts, the capital letters and the small letters represent distinct and unrelated entities. Those Greek letters which have the same form as Latin letters are rarely used: capital A, B, E, Z, H, I, K, M, N, O, P, T, Y, X. Small ι, ο and υ are also rarely used, since they closely resemble the Latin letters i, o and u. Sometimes, font variants of Greek letters are used as distinct symbols in mathematics, in particular for ε/ϵ and π/ϖ. The archaic letter digamma (Ϝ/ϝ/ϛ) is sometimes used.
The Bayer designation naming scheme for stars typically uses the first Greek letter, α, for the brightest star in each constellation, and runs through the alphabet before switching to Latin letters.
In mathematical finance, the Greeks are the variables denoted by Greek letters used to describe the risk of certain investments.
Some common conventions:
The Greek letter forms used in mathematics are often different from those used in Greek-language text: they are designed to be used in isolation, not connected to other letters, and some use variant forms which are not normally used in current Greek typography.
The OpenType font format has the feature tag "mgrk" ("Mathematical Greek") to identify a glyph as representing a Greek letter to be used in mathematical (as opposed to Greek language) contexts.
The table below shows a comparison of Greek letters rendered in TeX and HTML. The font used in the TeX rendering is an italic style. This is in line with the convention that variables should be italicized. As Greek letters are more often than not used as variables in mathematical formulas, a Greek letter appearing similar to the TeX rendering is more likely to be encountered in works involving mathematics.
Name | TeX | HTML |
---|---|---|
Alpha | Α α | |
Beta | Β β | |
Gamma | Γ γ | |
Delta | Δ δ | |
Epsilon | Ε ϵ ε | |
Digamma | Ϝ ϝ | |
Zeta | Ζ ζ | |
Eta | Η η | |
Theta | Θ θ ϑ | |
Iota | Ι ι | |
Kappa | Κ κ ϰ | |
Lambda | Λ λ | |
Mu | Μ μ |
Name | TeX | HTML |
---|---|---|
Nu | Ν ν | |
Xi | Ξ ξ | |
Omicron | Ο ο | |
Pi | Π π ϖ | |
Rho | Ρ ρ ϱ | |
Sigma | Σ σ ς | |
Tau | Τ τ | |
Upsilon | Υ υ | |
Phi | Φ ϕ φ | |
Chi | Χ χ | |
Psi | Ψ ψ | |
Omega | Ω ω |
Name | Greek Letter | Bold | Italic | Bold Italic | Sans-Serif Bold | Sans-Serif Bold Italic | APL | Double struck bold | Unicode variants or similar |
---|---|---|---|---|---|---|---|---|---|
Alpha | Α α | 𝚨 𝛂 | 𝛢 𝛼 | 𝜜 𝜶 | 𝝖 𝝰 | 𝞐 𝞪 | ⍺ ⍶ | ||
Beta | Β β ϐ ᵝ ᵦ | 𝚩 𝛃 | 𝛣 𝛽 | 𝜝 𝜷 | 𝝗 𝝱 | 𝞑 𝞫 | |||
Gamma | Γ γ ᴦ ᵞ ᵧ | 𝚪 𝛄 | 𝛤 𝛾 | 𝜞 𝜸 | 𝝘 𝝲 | 𝞒 𝞬 | ℾ ℽ | ||
Delta | Δ δ ᵟ | 𝚫 𝛅 | 𝛥 𝛿 | 𝜟 𝜹 | 𝝙 𝝳 | 𝞓 𝞭 | U+2206∆INCREMENT, U+2207∇NABLA | ||
Epsilon | Ε ε ϵ ϶ | 𝚬 𝛆 𝛜 | 𝛦 𝜀 𝜖 | 𝜠 𝜺 𝝐 | 𝝚 𝝴 𝞊 | 𝞔 𝞮 𝟄 | ⍷ | U+2208∈ELEMENT OF–U+220D∍SMALL CONTAINS AS MEMBER | |
Zeta | Ζ ζ | 𝚭 𝛇 | 𝛧 𝜁 | 𝜡 𝜻 | 𝝛 𝝵 | 𝞕 𝞯 | |||
Eta | Η η Ͱ ͱ | 𝚮 𝛈 | 𝛨 𝜂 | 𝜢 𝜼 | 𝝜 𝝶 | 𝞖 𝞰 | |||
Theta | Θ θ ϑ ϴ ᶿ | 𝚯 𝛉 𝚹 𝛝 | 𝛩 𝜃 𝛳 𝜗 | 𝜣 𝜽 𝜭 𝝑 | 𝝝 𝝷 𝚹 𝞋 | 𝞗 𝞱 𝜭 𝟅 | |||
Iota | Ι ι ᶥ ℩ | 𝚰 𝛊 | 𝛪 𝜄 | 𝜤 𝜾 | 𝝞 𝝸 | 𝞘 𝞲 | ⍳ ⍸ | ||
Kappa | Κ κ ϰ | 𝚱 𝛋 𝛞 | 𝛫 𝜅 𝜘 | 𝜥 𝜿 𝝒 | 𝝟 𝝹 𝞌 | 𝞙 𝞳 𝟆 | |||
Lambda | Λ λ ᴧ | 𝚲 𝛌 | 𝛬 𝜆 | 𝜦 𝝀 | 𝝠 𝝺 | 𝞚 𝞴 | |||
Mu | Μ μ | 𝚳 𝛍 | 𝛭 𝜇 | 𝜧 𝝁 | 𝝡 𝝻 | 𝞛 𝞵 | |||
Nu | Ν ν | 𝚴 𝛎 | 𝛮 𝜈 | 𝜨 𝝂 | 𝝢 𝝼 | 𝞜 𝞶 | |||
Xi | Ξ ξ | 𝚵 𝛏 | 𝛯 𝜉 | 𝜩 𝝃 | 𝝣 𝝽 | 𝞝 𝞷 | |||
Omicron | Ο ο | 𝚶 𝛐 | 𝛰 𝜊 | 𝜪 𝝄 | 𝝤 𝝾 | 𝞞 𝞸 | |||
Pi | Π π ϖ ᴨ | 𝚷 𝛑 𝛡 | 𝛱 𝜋 𝜛 | 𝜫 𝝅 𝝕 | 𝝥 𝝿 𝞏 | 𝞟 𝞹 𝟉 | ℿ ℼ | U+220F∏N-ARY PRODUCT, U+2210∐N-ARY COPRODUCT | |
Rho | Ρ ρ Ῥ ῥ ῤ ϱ ϼ ᴩ ᵨ ☧ | 𝚸 𝛒 𝛠 | 𝛲 𝜌 𝜚 | 𝜬 𝝆 𝝔 | 𝝦 𝞀 𝞎 | 𝞠 𝞺 𝟈 | ⍴ | ||
Sigma | Σ σ ς Ϲ ϲ Ͻ ͻ Ͼ ͼ Ͽ ͽ | 𝚺 𝛔 𝛓 | 𝛴 𝜎 𝜍 | 𝜮 𝝈 𝝇 | 𝝨 𝞂 𝞁 | 𝞢 𝞼 𝞻 | ⅀ | U+2211∑N-ARY SUMMATION | |
Tau | Τ τ | 𝚻 𝛕 | 𝛵 𝜏 | 𝜯 𝝉 | 𝝩 𝞃 | 𝞣 𝞽 | |||
Upsilon | Υ υ ϒ | 𝚼 𝛖 | 𝛶 𝜐 | 𝜰 𝝊 | 𝝪 𝞄 | 𝞤 𝞾 | |||
Phi | Φ φ ϕ | 𝚽 𝛗 𝛟 | 𝛷 𝜑 𝜙 | 𝜱 𝝋 𝝓 | 𝝫 𝞅 𝞍 | 𝞥 𝞿 𝟇 | |||
Chi | Χ χᵡᵪ☧ | 𝚾 𝛘 | 𝛸 𝜒 | 𝜲 𝝌 | 𝝬 𝞆 | 𝞦 𝟀 | |||
Psi | Ψ ψ ᴪ | 𝚿 𝛙 | 𝛹 𝜓 | 𝜳 𝝍 | 𝝭 𝞇 | 𝞧 𝟁 | |||
Omega | Ω ω ꭥ | 𝛀 𝛚 | 𝛺 𝜔 | 𝜴 𝝎 | 𝝮 𝞈 | 𝞨 𝟂 | ⍵ ⍹ | U+2126ΩOHM SIGN, U+2127℧INVERTED OHM SIGN |
Note: The empty set symbol ∅ looks similar, but is unrelated to the Greek letter.
Gamma is the third letter of the Greek alphabet. In the system of Greek numerals it has a value of 3. In Ancient Greek, the letter gamma represented a voiced velar stop IPA:[ɡ]. In Modern Greek, this letter normally represents a voiced velar fricative IPA:[ɣ], except before either of the two front vowels, where it represents a voiced palatal fricative IPA:[ʝ]; while /g/ in foreign words is instead commonly transcribed as γκ).
Omega is the twenty-fourth and last letter in the Greek alphabet. In the Greek numeric system/isopsephy (gematria), it has a value of 800. The word literally means "great O", as opposed to omicron, which means "little O".
The propagation constant of a sinusoidal electromagnetic wave is a measure of the change undergone by the amplitude and phase of the wave as it propagates in a given direction. The quantity being measured can be the voltage, the current in a circuit, or a field vector such as electric field strength or flux density. The propagation constant itself measures the dimensionless change in magnitude or phase per unit length. In the context of two-port networks and their cascades, propagation constant measures the change undergone by the source quantity as it propagates from one port to the next.
Phi is the twenty-first letter of the Greek alphabet.
Pi is the sixteenth letter of the Greek alphabet, meaning units united, and representing the voiceless bilabial plosive IPA:[p]. In the system of Greek numerals it has a value of 80. It was derived from the Phoenician letter Pe. Letters that arose from pi include Latin P, Cyrillic Pe, Coptic pi, and Gothic pairthra (𐍀).
Nu is the thirteenth letter of the Greek alphabet, representing the voiced alveolar nasal IPA:[n]. In the system of Greek numerals it has a value of 50. It is derived from the Phoenician nun . Its Latin equivalent is N, though the lowercase resembles the Roman lowercase v.
A sine wave, sinusoidal wave, or sinusoid is a periodic wave whose waveform (shape) is the trigonometric sine function. In mechanics, as a linear motion over time, this is simple harmonic motion; as rotation, it corresponds to uniform circular motion. Sine waves occur often in physics, including wind waves, sound waves, and light waves, such as monochromatic radiation. In engineering, signal processing, and mathematics, Fourier analysis decomposes general functions into a sum of sine waves of various frequencies, relative phases, and magnitudes.
Kappa is the tenth letter of the Greek alphabet, representing the voiceless velar plosive IPA:[k] sound in Ancient and Modern Greek. In the system of Greek numerals, Kʹ has a value of 20. It was derived from the Phoenician letter kaph . Letters that arose from kappa include the Roman K and Cyrillic К. The uppercase form is identical to the Latin K.
Psi(P)SY, (P)SEE is the twenty-third and penultimate letter of the Greek alphabet and is associated with a numeric value of 700. In both Classical and Modern Greek, the letter indicates the combination.
In functional analysis, a branch of mathematics, the Borel functional calculus is a functional calculus, which has particularly broad scope. Thus for instance if T is an operator, applying the squaring function s → s2 to T yields the operator T2. Using the functional calculus for larger classes of functions, we can for example define rigorously the "square root" of the (negative) Laplacian operator −Δ or the exponential
In physical systems, damping is the loss of energy of an oscillating system by dissipation. Damping is an influence within or upon an oscillatory system that has the effect of reducing or preventing its oscillation. Examples of damping include viscous damping in a fluid, surface friction, radiation, resistance in electronic oscillators, and absorption and scattering of light in optical oscillators. Damping not based on energy loss can be important in other oscillating systems such as those that occur in biological systems and bikes. Damping is not to be confused with friction, which is a type of dissipative force acting on a system. Friction can cause or be a factor of damping.
Many letters of the Latin alphabet, both capital and small, are used in mathematics, science, and engineering to denote by convention specific or abstracted constants, variables of a certain type, units, multipliers, or physical entities. Certain letters, when combined with special formatting, take on special meaning.
In mathematics, physics, and engineering, spatial frequency is a characteristic of any structure that is periodic across position in space. The spatial frequency is a measure of how often sinusoidal components of the structure repeat per unit of distance.
In mathematics, a variable is a symbol, typically a letter, that holds a place for constants, often numbers. One say colloqually that the variable represents or denotes the object, and that the object is the value of the variable.
In the mathematical discipline of set theory, there are many ways of describing specific countable ordinals. The smallest ones can be usefully and non-circularly expressed in terms of their Cantor normal forms. Beyond that, many ordinals of relevance to proof theory still have computable ordinal notations. However, it is not possible to decide effectively whether a given putative ordinal notation is a notation or not ; various more-concrete ways of defining ordinals that definitely have notations are available.
In classical mechanics, the Hannay angle is a mechanics analogue of the geometric phase. It was named after John Hannay of the University of Bristol, UK. Hannay first described the angle in 1985, extending the ideas of the recently formalized Berry phase to classical mechanics.
The history of mathematical notation includes the commencement, progress, and cultural diffusion of mathematical symbols and the conflict of the methods of notation confronted in a notation's move to popularity or inconspicuousness. Mathematical notation comprises the symbols used to write mathematical equations and formulas. Notation generally implies a set of well-defined representations of quantities and symbols operators. The history includes Hindu–Arabic numerals, letters from the Roman, Greek, Hebrew, and German alphabets, and a host of symbols invented by mathematicians over the past several centuries.
In computability theory, hyperarithmetic theory is a generalization of Turing computability. It has close connections with definability in second-order arithmetic and with weak systems of set theory such as Kripke–Platek set theory. It is an important tool in effective descriptive set theory.
In proof theory, ordinal analysis assigns ordinals to mathematical theories as a measure of their strength. If theories have the same proof-theoretic ordinal they are often equiconsistent, and if one theory has a larger proof-theoretic ordinal than another it can often prove the consistency of the second theory.
A variable speed wind turbine is one which is specifically designed to operate over a wide range of rotor speeds. It is in direct contrast to fixed speed wind turbine where the rotor speed is approximately constant. The reason to vary the rotor speed is to capture the maximum aerodynamic power in the wind, as the wind speed varies. The aerodynamic efficiency, or coefficient of power, for a fixed blade pitch angle is obtained by operating the wind turbine at the optimal tip-speed ratio as shown in the following graph.