ABSTRACT

One of the most important functions in mathematics and mathematical physics is the gamma function Γ(z). Among several equivalent definitions of Γ(z), we state the following () Γ ( z ) : = 2 π     z z − ( 1 / 2 ) e − z e J ( z ) , https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781003072126/15070696-a94f-4da5-a117-8ee069a896b3/content/eq1787.tif"/> which is given in terms of the Binet function J(z) defined by () J ( z ) z : = ∫ 0 ∞ υ ( t ) z + t   d t = : G J ( z ) , for z ∈ S π , https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781003072126/15070696-a94f-4da5-a117-8ee069a896b3/content/eq1788.tif"/> where () υ ( t ) : = 1 2 π 1 t Log 1 1 − e − 2 π t ,               0 < t < ∞ , https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781003072126/15070696-a94f-4da5-a117-8ee069a896b3/content/eq1789.tif"/> and () S θ : = [ z ∈ ℂ :   | arg z |   < θ ] ,               0 ≤ θ ≤ π . https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781003072126/15070696-a94f-4da5-a117-8ee069a896b3/content/eq1790.tif"/>