Report on WS25CCC

In the peak of the summer 2013, between the 7th and the 9th of August, the workshop “25 Years of Combining Compositionality and Concurrency” took place in Königswinter, a picturesque little town overlooking the Rhine river, in the outskirts of Bonn. The event, organised by Ursula Goltz, Rob van Glabbeek and Ernst-Rüdiger Olderog, was meant to celebrate and revisit, a quarter of a century later, the workshop “Combining Compositionality and Concurrency" (CCC88) that had been held in March 1988 in the same hotel, the Loreley, on the initiative of the same trio of researchers (the first two of which were still PhD students at the time). Both workshops were by invitation only, and each attracted 34 participants. Because of its timely character and its deliberate focus on bridging the gap between process calculi and “true-concurrency” models, the original CCC88 workshop, targeting a group of active researchers from both fields, had generated much enthusiasm and discussion. It had therefore gradually acquired, at least in the memories of its participants, the mythical status of a “foundational event”. It was then quite natural for the organisers, 25 years later, to envisage a kind of jubilee event, which could bring together a number of participants from the original workshop, as well as younger researchers who had joined in more recent years the field of concurrency theory, now much broader and well-established. It was by no Loreley deed1, but rather by a strong “community feeling”, that at least one third of the original participants responded positively to the invitation to the new event. This was certainly a high response rate for the season, considering that August is a “sacred” vacation month in most Southern European countries. Some important differences could be noticed between the two meetings, concerning the origin of participants and the scientific spectrum that was covered. While the 1988 workshop enjoyed a well-balanced European participation, including Eastern European countries such as Poland, and featured a limited but lively participation from non-European states such as Israel and California, the 2013 edition was more polarised towards Northern Europe (probably due to the “off-season” effect mentioned above), and its non-European participation fell down to a single person (Rob van Glabbeek), reaching as far as Australia. On the thematic side, while the 1988 workshop adopted a “fan-in” approach, inviting participants to concentrate on a specific topic, the 2013 workshop took