  In this note we present some of the most basic aspects of the fractional
Laplacean with a self-contained and purely didactic intent, and with a somewhat
different slant from the several excellent existing references. Given the
interest that nonlocal operators have generated since the 2007 extension paper
of Caffarelli and Silvestre, we feel it is appropriate offering to young
researchers a quick additional guide to the subject which, we hope, will nicely
complement the existing ones.
