The contribution The Reachability Problem for Petri Nets is Not Elementary by Wojciech Czerwinski, Slawomir Lasota, Ranko Lazic, Jerome Leroux and Filip Mazowiecki has won a Best Paper Award at the 51st Annual ACM Symposium on the Theory of Computing, to be held on June 23-26, 2019 in Phoenix, AZ.

This work, which was supported by a Leverhulme Research Fellowship, shows that the central verification problem for Petri nets is much harder than has been known since the landmark result of Richard Lipton in 1976. Petri nets, also known as vector addition systems, are a long established model of concurrency with extensive applications in modelling and analysis of hardware, software and database systems, as well as chemical, biological and business processes.

In January 2019, Dr. Charilaos Efthymiou joined the Department of Computer Science at the University of Warwick, as a member of the Division of Theory and Foundations (FoCS) and of the Centre for Discrete Mathematics and its Applications (DIMAP).

Before joining us, Charilaos held research positions in various universities including Goethe University of Frankfurt, Germany, as a DFG Fellow, College of Computing at Georgia Institute of Technology, USA, and School of Informatics a the University of Edinburgh, UK. This is not his first time at the University of Warwick, he has been a post-doc researcher at DIMAP (2010-2012). Charilaos completed his PhD at the University of Patras, Greece, in 2009.

His research is in the intersection of theory of algorithms, discrete mathematics and statistical physics. Specifically, he studies how powerful notions from statistical physics, e.g., phase transitions, affect the performance of algorithms for various problems in computer science and mathematics.

More information about Charilaos can be found on his personal web-page https://sites.google.com/site/charisefthymiou/.

The 2018 Open Mind Prize was awarded to Andrzej Grzesik, a postdoctoral researcher at the Department of Computer Science and a member of the DIMAP centre. The Open Mind Prize is awarded biennially during the Polish Combinatorial Conference to a junior Polish researcher for outstanding research in combinatorics. Andrzej completed his PhD in 2015 at Jagiellonian University in Kraków and joined the University of Warwick in October 2017. His research achievements include solutions to two extremal graph theory problems posed by Erdős and a conjecture of Lovász concerning finitely forcible graph limits.

In the Logic, Semantics, Automata and Theory of Programming track of the 45th International Colloquium on Automata, Languages, and Programming (ICALP), three out of 30 accepted papers are by members of the department. ICALP is one of the most selective and longest established international conferences in computer science, and the flagship annual event of the European Association for Theoretical Computer Science. The papers are:

• Reducing CMSO Model Checking to Highly Connected Graphs by Ramanujan M. S., Daniel Lokshtanov, Saket Saurabh and Meirav Zehavi
• O-Minimal Invariants for Linear Loops by Shaull Almagor, Dmitry Chistikov, Joel Ouaknine and James Worrell
• When is Containment Decidable for Probabilistic Automata? by Laure Daviaud, Ranko Lazić, Marcin Jurdziński, Filip Mazowiecki, Guillermo Perez and James Worrell

The Department will be welcoming Dr Laurent Doyen of CNRS and ENS Paris-Saclay as a Rutherford Visiting Fellow in 2018/19. This prestigious funding, whose aim is to attract top global talent into the UK, will allow Dr Doyen to collaborate closely with Dr Laure Daviaud, Dr Marcin Jurdzinski and Dr Ranko Lazic of DIMAP, as well as Dr Nathanael Fijalkow of the Alan Turing Institute, on cutting-edge research on fast algorithms for synthesis of safe, smart and adaptive controllers.

Professor Graham Cormode, the University of Warwick and Alan Turing Institute Liaison Director, commented:

Dr Doyen's Rutherford Visiting Fellowship will provide a major boost to building world-leading and long-lasting collaborative links among the Alan Turing Institute, the DIMAP multi-disciplinary research centre at Warwick, and LSV at ENS Paris-Saclay. The latter is an established European centre of excellence in logical aspects of computer and data sciences.

The Theory and Foundations Division is welcoming Dr Laure Daviaud, who will be the Research Fellow working with Dr Marcin Jurdzinski and Dr Ranko Lazic on the EPSRC project on Parity Games.

Prior to coming to Warwick, Laure was a postdoc on the ERC project Lipa (Uniwersytet Warszawski), as well as at LIP (ENS Lyon) and LIF (Université d'Aix-Marseille). She obtained her PhD at LIAFA (Université Paris Diderot, CNRS).

Laure's research interests include automata theory, verification, logic, quantitative models and transducers, weighted automata, streaming models, algebraic language theory and topology, tropical algebra and semigroup of matrices.