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Many Roman letters, 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, physical entities. Certain letters, when combined with special formatting, take on special meaning.## Aa

## Bb

## Cc

## Dd

## Ee

## Ff

## Gg

## Hh

## Ii

## Jj

## Kk

## Ll

## Mm

## Nn

## Oo

## Pp

## Qq

## Rr

## Ss

## Tt

## Uu

## Vv

## Ww

## Xx

## Yy

## Zz

## See also

Below is an alphabetical list of the letters of the alphabet with some of their uses. The field in which the convention applies is mathematics unless otherwise noted.

- A represents:
- the first corner of a triangle
- the digit "10" in hexadecimal and other positional numeral systems with a radix of 11 or greater
- the unit ampere for electrical current
- area
- $mathbb\{A\}$ represents the algebraic numbers or affine space in Algebraic Geometry
- a represents:
- the first side of a triangle (opposite corner A)
- the acceleration in mechanics equations
- the x-intercept of a line
- the unit are for area (100 m²)
- the unit prefix atto (10
^{−18}) - the first term in a sequence or series (eg. S
_{n}= n(a+l)/2)

- B represents:
- the digit "11" in hexadecimal and other positional numeral systems with a radix of 12 or greater
- the second corner of a triangle
- a ball (also denoted by $mathcal\{B\}$ or $mathbb\{B\}$)
- a basis of a vector space or of a filter (both also denoted by $mathcal\{B\}$)
- B with various subscripts represents several variations of Brun's constant and Betti numbers
- b represents:
- the second side of a triangle (opposite corner B)
- the y-intercept of a line
- (usually with an index, sometimes with an arrow over it) a basis vector

- C represents:
- the third corner of a triangle
- the digit "12" in hexadecimal and other positional numeral systems with a radix of 13 or greater
- the unit coulomb of electrical charge
- C with indices denotes the number of combinations, a binomial coefficient
- $mathbb\{C\}$ represents the set of complex numbers
- A vertically elongated C with an integer subscript n sometimes denotes the n-th coefficient of a formal power series.
- c represents:
- the third side of a triangle (opposite corner C)
- the unit prefix centi (10
^{−2}) - c represents:
- the speed of light in vacuum
- Small bold C denotes the cardinality of the set of real numbers (the "continuum"), or,

equivalently, of the power set of natural numbers

- D represents the digit "13" in hexadecimal and other positional numeral systems with a radix of 14 or greater
- d represents
- the differential operator
- the unit day of time (86 400 s)
- the difference in an arithmetic sequence (eg. S
_{n}= n(2a+(n-1)d)/2)

- E represents:
- the digit "14" in hexadecimal and other positional numeral systems with a radix of 15 or greater
- an exponent in decimal numbers 1.2E3 is 1.2×10³ or 1200
- the set of edges in a graph or matroid
- the unit prefix exa (10
^{18}) - Energy in physics
- e represents:
- Euler's number, a transcendental number equal to 2.71828182845… which is used as the base for natural logarithms
- a vector of unit length, especially in the direction of one of the coordinates axes
- the elementary charge in physics

- F represents
- the digit "15" in hexadecimal and other positional numeral systems with a radix of 16 or greater
- force in mechanics equations
- the probability distribution function in statistics
- the unit farad of electrical capacity
- f represents:

- G represents
- an arbitrary graph, as in: G(V,E)
- an arbitrary group
- the unit prefix giga (10
^{9}) - Newton's gravitational constant
- the Einstein tensor
- g represents:
- the generic designation of a second function
- the acceleration due to gravity on Earth

- H represents:
- a Hilbert space
- the unit henry of magnetic inductance
- the homology and cohomology functors
- h represents:
- a small increment in the argument of a function
- the unit hour for time (3600 s)
- the Planck constant (6.624 608 96(33) × 10
^{-34}J·s) - the unit prefix hecto (10²)
- $mathbb\{H\}$ represents the quaternions (after William Rowan Hamilton, representing the rationals)
- $mathcal\{H\}$ represents the Hamiltonian in Hamiltonian mechanics

- I represents:
- the closed unit interval, which contains all real numbers from 0 to 1, inclusive
- the identity matrix
- i represents:
- the imaginary unit, a complex number that is the square root of −1
- a subscript to denote the ith term (that is, a general term or index) in a sequence or list
- the index to the elements of a vector, written as a subscript after the vector name
- the index to the rows of a matrix, written as the first subscript after the matrix name
- an index of summation using the sigma notation

- J represents the unit joule of energy
- j represents:
- the index to the columns of a matrix, written as the second subscript after the matrix name
- in electrical engineering, the square root of −1, instead of i
- in electrical engineering, the principal cube root of 1: $-frac\{1\}\{2\}+frac\{1\}\{2\}i\; sqrt\; 3$

- K represents:
- k represents
- the unit prefix kilo- (10³)
- the Boltzmann constant
- an integer, e.g. a dummy variable in summations, or an index of a matrix.
- an unspecified (real) constant

- L represents:
- the unit litre of volume
- the space of all integrable real (or complex) functions
- the space of linear maps, as in L(E,F) or L(E) = End(E)
- the Likelihood function
- l represents:
- the length of a side of a rectangle or a rectangular prism (eg. V = lwh; A = lw)
- the last term of a sequence or series (eg. S
_{n}= n(a+l)/2) - $mathcal\{L\}$ (or sometimes just L) represents the Lagrangian

- M represents:
- a manifold
- a metric space
- a matroid
- the unit prefix mega (10
^{6}) - m represents:

- N represents
- the unit newton of force
- N
_{A}represents the Avogadro constant which is the number of entities in one mole (used mainly in the counting of molecules and atoms) - $mathbb\{N\}$ represents the natural numbers
- n represents

- O represents the order of asymptotic behavior of a function; see Big O notation
- O represents $(0,0,ldots,0)$ — the origin of the coordinate system in Cartesian coordinates

- P represents:
- the pressure in physics equations
- the unit prefix peta (10
^{15}) - $mathbb\{P\}$ represents
- p represents the unit prefix pico (10
^{−12})

- $mathbb\{Q\}$ represents the rational numbers

- R represents:
- the Ricci tensor
- $mathbb\{R\}$ represents the set of real numbers and various algebraic structures built upon the set of real numbers, such as $mathbb\{R\}^n$
- r represents:
- the radius of a circle or sphere
- the ratio of a geometric series (eg. ar
^{n-1})

- S represents
- a sum
- the unit siemens of electric conductance
- the unit sphere (with superscript denoting dimension)
- the scattering matrix
- s represents:
- $mathcal\{S\}$ represents a system's action in physics

- T represents:
- the top element of a lattice
- a tree (a special kind of graph)
- temperature in physics equations
- the unit tesla of magnetic flux density
- the unit prefix tera (10
^{12}) - the stress-energy tensor
- t represents:
- time in graphs, functions or equations
- a term in a sequence or series (eg. t
_{n}= t_{n-1}+5)

- U represents:
- a U-set which is a set of uniqueness
- a unitary operator
- U(n) represents the unitary group of degree n
- ∪ represents the union operator

- V represents:
- v represents the velocity in mechanics equations

- W represents the unit watt of power

- x represents
- an unknown variable, most often (but not always) from the set of real numbers, while a complex unknown would rather be called z, and an integer by a letter like m from the middle of the alphabet.
- the coordinate on the first or horizontal axis in a cartesian coordinate system, the viewport in a graph or window in computer graphics

- Y represents:
- the unit prefix yotta (10
^{24}) - y represents:
- the unit prefix yocto (10
^{−24}) - y represents:

- Z represents:
- the unit prefix zetta (10
^{21}) - a standarized normal random variable in Probability Theory and Statistics
- $mathbb\{Z\}$ represents the integers
- z represents:
- the unit prefix zepto (10
^{−21}) - the coordinate on the third or vertical axis in three dimensional space
- the view depth in computer graphics, see also "z-buffering"
- the argument of a complex function, or any other variable used to represent a complex value

- Greek letters used in mathematics
- Latin alphabet
- Mathematical alphanumeric symbols
- Table of mathematical symbols
- Typographical conventions in mathematical formulae

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Last updated on Tuesday August 19, 2008 at 05:22:39 PDT (GMT -0700)

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This article is licensed under the GNU Free Documentation License.

Last updated on Tuesday August 19, 2008 at 05:22:39 PDT (GMT -0700)

View this article at Wikipedia.org - Edit this article at Wikipedia.org - Donate to the Wikimedia Foundation

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