The first 36 months of the DIAPASoN project served to bootstrap the team and to get the first definite results. Indeed, the injection of six postdocs (Aurore Alcolei, Francesco Gavazzo, Guillaume Geoffrey, Paolo Pistone, Alexis Ghyselen, Maurizio Murgia) and two junior researchers (Andrea Colledan and Cecilia Di Florio) in the workgroup allowed the team to start working on the four WPs, and to obtain the first results on all of them. Collaborations between the project participants has been made possible by regular physical meetings at the host institution, weekly seminars, and online exchanges - a SLACK workplace specifically about DIAPASoN has been created and is used to exchange information. Online collaborative tools proved to be very useful during the covid19 pandemic: lockdown was enforced in Italy starting from March 8th, 2020, and physical meetings at the host institution were impossible (until May 4th, 2020) and highly discouraged (afterwards). The DIAPASoN kickoff meeting took place at IRIF (Paris) on February 26 to February 28, 2020, co-located with the CRECOGI and PPS workshops (see
https://www.irif.fr/pps-pihoc-diapason2020). The second DIAPASoN meeting took place online in February 2021, again co-located with the PPS workshop. (see
https://www.irif.fr/pps-pihoc-diapason2021). Given the high number of participants (more than one hundred researchers registered for the two events), this has been a very good occasion to share the first results obtained in the project with nearby research communities, and to receive feedback. In the first half of this project, results obtained in the project appeared in top journals and conferences on programming language theory, including ICALP, ESOP, POPL, LICS and SCP.