 This recent emphasis on systems in interaction is part of a more general shift of attention away from the static structure of states and observables and towards the processes in which physical systems can participate. This trend is evident not only in the category-theoretic formulation of Abramsky and Coecke (see also Coecke [2011]), but also in several recent axiomatic reconstructions of quantum theory (e.g., Hardy [2001, Other Internet Resources], Rau [2009], Dakic-Brukner [2011], Massanes and Mueller [2011], Chiribella-D’Ariano-Perinotti [2011], Wilce [2018]), most of which involve assumptions about how physical systems combine. In a different direction, Baltag and Smets [2005] enrich a Piron-style lattice-theoretic framework with an explicitly dynamical element, arriving at a quantum analogue of propositional dynamical logic.