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1: 5.11 Asymptotic Expansions
§5.11 Asymptotic Expansions
The scaled gamma function Γ ( z ) is defined in (5.11.3) and its main property is Γ ( z ) 1 as z in the sector | ph z | π δ . …
§5.11(ii) Error Bounds and Exponential Improvement
§5.11(iii) Ratios
2: Errata
  • Rearrangement

    In previous versions of the DLMF, in §8.18(ii), the notation Γ ~ ( z ) was used for the scaled gamma function Γ ( z ) . Now in §8.18(ii), we adopt the notation which was introduced in Version 1.1.7 (October 15, 2022) and correspondingly, Equation (8.18.13) has been removed. In place of Equation (8.18.13), it is now mentioned to see (5.11.3).

  • Additions

    Equations: (5.9.2_5), (5.9.10_1), (5.9.10_2), (5.9.11_1), (5.9.11_2), the definition of the scaled gamma function Γ ( z ) was inserted after the first equals sign in (5.11.3), post equality added in (7.17.2) which gives “ = m = 0 a m t 2 m + 1 ”, (7.17.2_5), (31.11.3_1), (31.11.3_2) with some explanatory text.

  • Subsection 15.2(ii)

    The unnumbered equation

    lim c n F ( a , b ; c ; z ) Γ ( c ) = 𝐅 ( a , b ; n ; z ) = ( a ) n + 1 ( b ) n + 1 ( n + 1 ) ! z n + 1 F ( a + n + 1 , b + n + 1 ; n + 2 ; z ) , n = 0 , 1 , 2 ,

    was added in the second paragraph. An equation number will be assigned in an expanded numbering scheme that is under current development. Additionally, the discussion following (15.2.6) was expanded.

  • Chapters 8, 20, 36

    Several new equations have been added. See (8.17.24), (20.7.34), §20.11(v), (26.12.27), (36.2.28), and (36.2.29).

  • Equation (14.19.2)
    14.19.2 P ν 1 2 μ ( cosh ξ ) = Γ ( 1 2 μ ) π 1 / 2 ( 1 e 2 ξ ) μ e ( ν + ( 1 / 2 ) ) ξ 𝐅 ( 1 2 μ , 1 2 + ν μ ; 1 2 μ ; 1 e 2 ξ ) , μ 1 2 , 3 2 , 5 2 ,

    Originally the argument to 𝐅 in this equation was incorrect ( e 2 ξ , rather than 1 e 2 ξ ), and the condition on μ was too weak ( μ 1 2 , rather than μ 1 2 , 3 2 , 5 2 , ). Also, the factor multiplying 𝐅 was rewritten to clarify the poles; originally it was Γ ( 1 2 μ ) 2 2 μ Γ ( 1 μ ) ( 1 e 2 ξ ) μ e ( ν + ( 1 / 2 ) ) ξ .

    Reported 2010-11-02 by Alvaro Valenzuela.

  • 3: Bibliography F
  • FDLIBM (free C library)
  • C. Ferreira, J. L. López, and E. Pérez Sinusía (2005) Incomplete gamma functions for large values of their variables. Adv. in Appl. Math. 34 (3), pp. 467–485.
  • C. Ferreira and J. L. López (2001) An asymptotic expansion of the double gamma function. J. Approx. Theory 111 (2), pp. 298–314.
  • A. M. S. Filho and G. Schwachheim (1967) Algorithm 309. Gamma function with arbitrary precision. Comm. ACM 10 (8), pp. 511–512.
  • P. J. Forrester and N. S. Witte (2004) Application of the τ -function theory of Painlevé equations to random matrices: P VI , the JUE, CyUE, cJUE and scaled limits. Nagoya Math. J. 174, pp. 29–114.
  • 4: Bibliography G
  • W. Gautschi (1979a) Algorithm 542: Incomplete gamma functions. ACM Trans. Math. Software 5 (4), pp. 482–489.
  • W. Gautschi (1959b) Some elementary inequalities relating to the gamma and incomplete gamma function. J. Math. Phys. 38 (1), pp. 77–81.
  • W. Gautschi (1974) A harmonic mean inequality for the gamma function. SIAM J. Math. Anal. 5 (2), pp. 278–281.
  • W. Gautschi (1979b) A computational procedure for incomplete gamma functions. ACM Trans. Math. Software 5 (4), pp. 466–481.
  • A. Gil, J. Segura, and N. M. Temme (2014) Algorithm 939: computation of the Marcum Q-function. ACM Trans. Math. Softw. 40 (3), pp. 20:1–20:21.