In mathematics, by sigma function one can mean one of the following:
The sum-of-divisors function σa(n), an arithmetic function
Weierstrass sigma function, related to elliptic functions
Rado's sigma function, see busy beaver
See also sigmoid function.
Topics referred to by the same term
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mathematics, by sigmafunction one can mean one of the following: The sum-of-divisors function σa(n), an arithmetic function Weierstrass sigmafunction, related...
theory, σ is included in various divisor functions, especially the sigmafunction or sum-of-divisors function. In applied mathematics, σ(T) denotes the...
between the sigma, zeta, and ℘ {\displaystyle \wp } functions is analogous to that between the sine, cotangent, and squared cosecant functions: the logarithmic...
the number-of-divisors function (OEIS: A000005). When z is 1, the function is called the sigmafunction or sum-of-divisors function, and the subscript is...
probabilities. Formally, the standard (unit) softmax function σ : R K → ( 0 , 1 ) K {\displaystyle \sigma \colon \mathbb {R} ^{K}\to (0,1)^{K}} , where K ≥...
density function is f ( x ) = 1 2 π σ 2 e − ( x − μ ) 2 2 σ 2 {\displaystyle f(x)={\frac {1}{\sqrt {2\pi \sigma ^{2}}}}e^{-{\frac {(x-\mu )^{2}}{2\sigma ^{2}}}}}...
respective σ {\displaystyle \sigma } -algebras Σ {\displaystyle \Sigma } and T . {\displaystyle \mathrm {T} .} A function f : X → Y {\displaystyle f:X\to...
logistic function shown in the first figure and defined by the formula: σ ( x ) = 1 1 + e − x = e x 1 + e x = 1 − σ ( − x ) . {\displaystyle \sigma (x)={\frac...
Six Sigma (6σ) is a set of techniques and tools for process improvement. It was introduced by American engineer Bill Smith while working at Motorola in...
a transfer function (also known as system function or network function) of a system, sub-system, or component is a mathematical function that models...
asymptotically faster than any computable function. The busy beaver function, Σ : N → N {\displaystyle \Sigma :\mathbb {N} \to \mathbb {N} } , is defined...
to the origin (zero point) Sigmafunction: Sums of powers of divisors of a given natural number. Euler's totient function: Number of numbers coprime to...
starvation/stationary phase sigma factor σ54 (RpoN) – the nitrogen-limitation sigma factor There are also anti-sigma factors that inhibit the function of sigma factors and...
{\displaystyle V(x;\sigma ,\gamma )={\frac {\operatorname {Re} [w(z)]}{{\sqrt {2\pi }}\,\sigma }},} where Re[w(z)] is the real part of the Faddeeva function evaluated...
probability density function of f ( x , μ , σ 2 ) = 1 σ 2 π e − 1 2 ( x − μ σ ) 2 {\displaystyle f\left(x,\mu ,\sigma ^{2}\right)={\frac {1}{\sigma {\sqrt {2\pi...
k\times k} matrix Σ {\displaystyle {\boldsymbol {\Sigma }}} , such that the characteristic function of X {\displaystyle \mathbf {X} } is φ X ( u ) = exp...
density function of the Rayleigh distribution is f ( x ; σ ) = x σ 2 e − x 2 / ( 2 σ 2 ) , x ≥ 0 , {\displaystyle f(x;\sigma )={\frac {x}{\sigma ^{2}}}e^{-x^{2}/(2\sigma...
In mathematics, the error function (also called the Gauss error function), often denoted by erf, is a function defined as: erf z = 2 π ∫ 0 z e − t 2...