“…The flexibility introduced by structural sets ensembles makes it possible to seek new perspectives in investigations concerning the mapping properties of multidimensional Ahlfors–Beurling transforms and additive decompositions of harmonic functions [
16, 19–26]. This permits us to consider a much wider class of second‐order partial differential equation from two given structural sets
and
, that is, the general sandwich equation
whose solutions have been referred to as
‐inframonogenic functions (see prior research [
5, 11, 27–30]).…”