  We present a new functional setting for Neumann conditions related to the
superposition of (possibly infinitely many) fractional Laplace operators. We
will introduce some bespoke functional framework and present minimization
properties, existence and uniqueness results, asymptotic formulas, spectral
analyses, rigidity results, integration by parts formulas, superpositions of
fractional perimeters, as well as a study of the associated heat equation.
