where, and are nonterminal symbols, α is a terminal symbol ( a symbol that represents a constant value ), is the start symbol, and ε is the empty string.

where, and are nonterminal symbols, and α is a terminal symbol.

In the following descriptions, α, β, and γ represent any string of terminals / nonterminals ( including the empty string ), X and Y represent single nonterminals, and a represents a terminal symbol.

* Scanning: If a is the next symbol in the input stream, for every state in S ( k ) of the form ( X → α • a β, j ), add ( X → α a • β, j ) to S ( k + 1 ).

Right ascension ( abbreviated RA ; symbol α ) is the astronomical term for one of the two direction coordinates of a point on the celestial sphere in the equatorial coordinate system, usually combined with declination.

where A is a nonterminal symbol, α is a terminal symbol,

FOLLOW ( I ) of an Item I → α • B β, x is the set of terminals that can appear after nonterminal B, where α, β are arbitrary symbol strings, and x is an arbitrary lookahead terminal.

The significance level is usually denoted by the Greek symbol α ( lowercase alpha ).

* α, the conventional symbol for angular eccentricity

* α, a symbol for navigational azimuth

* α, a symbol for one of the Feigenbaum constants describing a bifurcation diagram, in mathematics

* α, a symbol representing the probability of a type I error in statistics

* α, a symbol for the angle of attack in aerodynamics

* α, a symbol for coefficient of thermal expansion in thermodynamics

* α, a symbol for the fine-structure constant in physics

* α, a symbol for thermal diffusivity in thermodynamics

* α, a symbol for common-base current gain of a transistor in electronics

where α and β are arbitrary scaling constants and represents the tensor product ( which is not related to the vector cross product, despite their similar symbol ).

Untriseptium, element 137, is sometimes called feynmanium ( symbol Fy ) because Richard Feynman noted that a simplistic interpretation of the relativistic Dirac equation runs into problems with electron orbitals at Z > 1 / α = 137, suggesting that neutral atoms cannot exist beyond untriseptium, and that a periodic table of elements based on electron orbitals therefore breaks down at this point.

Arcturus is notable for its high proper motion, larger than any first magnitude star in the stellar neighborhood other than α Centauri.

for an arbitrary real or complex number α ( the order of the Bessel function ); the most common and important cases are for α an integer or half-integer.

Although α and − α produce the same differential equation, it is conventional to define different Bessel functions for these two orders ( e. g., so that the Bessel functions are mostly smooth functions of α ).

Bessel functions of the first kind, denoted as J < sub > α </ sub >( x ), are solutions of Bessel's differential equation that are finite at the origin ( x = 0 ) for integer α, and diverge as x approaches zero for negative non-integer α.

Plot of Bessel function of the first kind, J < sub > α </ sub >( x ), for integer orders α = 0, 1, 2.

On the other hand, for integer order α, the following relationship is valid ( note that the Gamma function becomes infinite for negative integer arguments ):

Plot of Bessel function of the second kind, Y < sub > α </ sub >( x ), for integer orders α = 0, 1, 2.

When α is an integer, moreover, as was similarly the case for the functions of the first kind, the following relationship is valid:

For integer order α = n, J < sub > n </ sub > is often defined via a Laurent series for a generating function:

This orthogonality relation can then be used to extract the coefficients in the Fourier – Bessel series, where a function is expanded in the basis of the functions J < sub > α </ sub >( x u < sub > α, m </ sub >) for fixed α and varying m.

where α is the fine-structure constant and j is a number which is the total angular momentum eigenvalue ; that is, depending on the direction of the electron spin.

This approximation is accurate only in small angles because of the expression for angular acceleration α being proportional to the sine of position:

where α is the angular acceleration of the body, measured in rad · s < sup >− 2 </ sup >.

where the pseudovectors τ and L are, respectively, the torque on the gyroscope and its angular momentum, the scalar I is its moment of inertia, the vector ω is its angular velocity, and the vector α is its angular acceleration.

Proper motion may also be given by the angular changes per year in the right ascension ( μ < sub > α </ sub >) and declination ( μ < sub > δ </ sub >).

where α is the constant angular acceleration, ω is the angular velocity, ω < sub > 0 </ sub > is the initial angular velocity, θ is the angle turned through ( angular displacement ), θ < sub > 0 </ sub > is the initial angle, and t is the time taken to rotate from the initial state to the final state.

The angular diameter of the red giant, α < sup > 1 </ sup > Her, has been measured with an interferometer as

: α is called the angular acceleration ( or rotational acceleration ) about the rotation axis.

For no distortion, α is required to be constant with angular frequency ω, while β must be proportional to ω.

where τ is the net torque ( or moment ) exerted on the vehicle, I < sub > x </ sub > is its moment of inertia about the axis of rotation, and α is the angular acceleration vector in radians per second per second.

and the angular rotation rate ω ( degrees per second ) is obtained by integrating α over time, and the angular rotation θ is the time integral of the rate, analogous to linear motion.

For a given angular aperture, α, of the incoming light, this concentration will be maximum for the maximum value of β, that is β = π / 2.

Polar distance ( PD ) is an astronomical term associated with the celestial equatorial coordinate system Σ ( α, δ ) and it is an angular distance of a celestial object on its meridian measured from the celestial pole, similar as declination ( dec, δ ) is measured from the celestial equator: