Logarithmic derivative of the Euler $\Gamma$-function in Clifford analysis

Abstract

The logarithmic derivative of the $\Gamma$-function, namely the $\psi$-function, has numerous applications. We define analogous functions in a four dimensional space. We cut lattices and obtain Clifford-valued functions. These functions are holomorphic cliffordian and have similar properties as the $\psi$-function. These new functions show links between well-known constants: the Euler gamma constant and some generalisations, ${\zeta }^R(2)$, ${\zeta }^R(3)$. We get also the Riemann zeta function and the Epstein zeta functions.