This talk is an informal presentation of ideas put forward by Badouel, Bernardinello, Caillaud and me for solving various types of P/T-net synthesis problems, with hints at the potential role of net synthesis in distributed software and distributed control. The ideas are theirs as much as mine. The lead is to start from Ehrenfeucht and Rozenberg’s axiomatic characterization of behaviours of elementary nets, based on regions, to adapt the characterization to P/T-nets in line with Mukund’s extended regions with integer values, and to profit from algebraic properties of graphs and languages for converting decision problems about regions to linear algebra.