Preface

The Fifth International Conference on Applied Category Theory took place at the University of Strathclyde on 18−22 July 2022, following the previous meetings at Leiden (2018), Oxford (2019), MIT (2020, fully online), and Cambridge (2021). It was preceded by the Adjoint School 2022 (11−15 July), a collaborative research event in which junior researchers worked on cutting-edge topics under the mentorship of experts. The conference comprised 59 contributed talks, a poster session, an industry showcase session, and a session where junior researchers who had attended the Adjoint School presented the results of their research at the school. Information regarding the conference may be found at https://msp.cis.strath.ac.uk/act2022.

ACT 2022 was a hybrid event, with physical attendees present in Glasgow and other participants taking part online. All talks were streamed to YouTube and with synchronous discussion on Zulip. Links to recordings of the talks as well as notes taken during the conference may be found at https://statebox.tv/act2022.

Submission to ACT2022 had three tracks: extended abstracts, software demonstrations, and proceedings. The extended abstract and software demonstration submissions had a page limit of 2 pages, and the proceedings track had a page limit of 14 pages. Only papers submitted to the proceedings track were considered for publication in this volume. ACT2022 was the first year with a software demonstration track. In total, there were 97 submissions, of which 59 were accepted for presentation and 24 for publication in this volume. Publication of accepted submissions in the proceedings was determined by personal choice of the authors and not based on quality. Each submission received a review from three different members of the programming committee, and papers were selected based on discussion and consensus by these reviewers.

The contributions to ACT2022 ranged from pure to applied and included contributions in a wide range of disciplines in science and engineering. ACT2022 included talks in linguistics, functional programming, classical mechanics, quantum physics, probability theory, electrical engineering, epidemiology, thermodynamics, engineering, and logic. The quality of submissions to ACT2022 was very high, containing both cutting-edge category theory and a high degree of relevance to the chosen application. Many of the submissions had software demonstrating their work or represented work done in collaboration with industry or a scientific organization. The industry session included 10 invited talks by practitioners using category theory in private enterprise. ACT2022 was sponsored by Huawei, Protocol Labs, Cambridge Quantum, Conexus, Topos, and SICSA (Scottish Informatics and Computer Science Alliance).

ACT2022 was the first meeting since the inaugural which was not severely affected by COVID-19. The conference saw the community return in full force with more attendees, submissions, and general initiatives than previous editions of the conference. In particular, we were inspired by how many new people from a very wide range of backgrounds have joined in research with the applied category theory community. We hope that ACT, the conference and the community, continue to grow in future years. We are excited to see the new developments at ACT2023.

Jade Master and Martha Lewis
Chairs of the ACT 2022 Programme Committee