A four dimensional Jensen formula
arXiv:1902.06485
Abstract
We prove a Jensen formula for slice-regular functions of one quaternionic variable. The formula relates the value of the function and of its first two derivatives at a point with its integral mean on a three dimensional sphere centred at that point and with the disposition of its zeros. The formula can be extended to semiregular slice functions.
Accepted for publication on Riv. Mat. Univ. Parma