On the Laurent series Expansions of the Barnes Double Zeta-Function

The Laurent series expansions of complex functions play a crucial role in analyzing their behavior near poles. In particular, Laurent series expansions have been extensively studied in the theory of zeta-functions. It is well known that the Laurent series expansion of the Riemann zeta-function features the Euler-Stieltjes constants in its coefficients. Similar phenomena occur in the Laurent series expansion of the Hurwitz zeta-function, which is of considerable interest. In this paper, we compute the Laurent series expansions of the Barnes double zeta-function ζ₂ (s, α; v, w) at s=1 and s=2, and show that a constant analogous to the Euler-Stieltjes constant appears in the constant term.