================================================================================ P9419 J.C.M. Baeten, J.A. Bergstra & Gh. Stefanescu "Process algebra with feedback" We consider process graphs over a set of pins, i.e., with multiple entries and exits. On process graphs modulo bisimulation, we can define all standard process algebra operators plus the feedback operator from flowchart theory. We provide a complete axiomatisation for finite processes. Considering the one-point pin structure, we get back standard process algebra. TO APPEAR IN: A. Ponse, Y. Venema, and M. de Rijke, editors. Modal Logic and Process Algebra, a Bisimulation Perspective. CSLI.