Gamma function

E146428

The Gamma function is a fundamental extension of the factorial function to complex and real non-integer arguments, widely used in analysis, probability, and mathematical physics.

All labels observed (3)

Label Occurrences
Gamma function canonical 7
Gamma function identities 1
gamma function 1

How this entity was disambiguated

Statements (50)

Predicate Object
instanceOf extension of factorial
meromorphic function
special function
agreesWithFactorialOn Γ(n+1)=n! for n∈ℕ
alsoDevelopedBy Adrien-Marie Legendre
appearsIn Student’s t-distribution
beta distribution
chi-square distribution
gamma distribution
codomain complex numbers
containsConstant Euler–Mascheroni constant γ
definedOn complex numbers except non-positive integers
domain complex plane minus non-positive integers
generalizes factorial function to non-integers
growthOrder order 1 in complex plane
hasDuplicationFormula Γ(z)Γ(z+1/2)=2^{1-2z}√π Γ(2z)
hasIntegralRepresentation Γ(z)=∫₀^∞ t^{z-1}e^{-t}dt for Re(z)>0
hasLogarithmicDerivative digamma function
hasMultiplicationFormula Gauss multiplication formula
hasReflectionFormula Γ(z)Γ(1−z)=π/sin(πz)
hasSimplePolesAt z=0,-1,-2,…
hasWeierstrassProduct 1/Γ(z)=ze^{γz}∏_{n=1}^∞(1+z/n)e^{-z/n}
introducedBy Leonhard Euler
isEvenOrOdd neither even nor odd
isHolomorphicOn ℂ minus non-positive integers
isLogarithmicallyConvexOn (0,∞)
isLogConvexOn (0,∞)
nonZeroOn right half-plane Re(z)>0
normalizationConstantFor Dirichlet distribution
surface form: Dirichlet distribution density

beta distribution density
gamma distribution density
relatedFunction Euler’s reflection formula
beta function
incomplete gamma function
polygamma function
satisfiesFunctionalEquation Γ(z+1)=zΓ(z)
satisfiesRecurrence Γ(z+1)=zΓ(z)
satisfiesStirlingApproximation Γ(z)~√(2π) z^{z-1/2} e^{-z} as |z|→∞ in sector
symbol Γ(z)
usedIn asymptotic analysis
complex analysis
mathematical physics
number theory
probability theory
representation of distributions
statistics
valueAt Γ(1)=1
Γ(1/2)=√π
Γ(n)=(n-1)! for n∈ℕ
yearIntroducedApprox 18th century

How these facts were elicited

Referenced by (9)

Full triples — surface form annotated when it differs from this entity's canonical label.

Gaussian integral relatedTo Gamma function
Riemann–Siegel formula involves Gamma function
Pochhammer symbol usedIn Gamma function
this entity surface form: Gamma function identities
Pochhammer symbol relatedTo Gamma function
Selberg integral relatedTo Gamma function
this entity surface form: gamma function
Stirling's approximation appliesTo Gamma function