As in [Entire slice regular functions, Springer, 2016] we define the ∗-exponential of a slice-regular function, which can be seen as a generalization of the complex exponential to quaternions.

What’s the greatest shortcoming of the human race? I’m sure we all have some suggestions, but according to physicist Albert Bartlett, it is “our inability to understand the exponential function.” ...

A PHASE relation familiar to students of applied mathematics exists between a simple harmonic oscillation and its derivative. Similar relations exist between exponential functions and their ...