ARCO, an acronym for Algorithmic Research Cooperation around Øresund, is a network for promoting collaboration in research within algorithms around the Øresund Region. This time, the ARCO meeting was held at ITU and attended by Kim Skak Larsen, Joan Boyar, Kevin Schewior, Simon Skjernaa Erfurth, Magnus Berg, and Rolf Fagerberg. Kevin gave a talk on The Itinerant List Update Problem.

Joan Boyar and Kim Skak Larsen joined the 24-hour DDC meeting at Storebælt Sinatur Hotel & Konference, together with their Ph.D. student, Simon Skjernaa Erfurth. We enjoyed an informative meeting, updating us on the status of the various projects, while time was also reserved for discussions on how the Digital Democracy Center could develop.

The Teaching Prize at SDU is awarded once a year to one person. Given that SDU has a few thousand employees, getting the award is quite an achievement! Lene receives the prize for her special ability to make very complex material understandable. The prize is in recognition of her didactic approach, described by the students as elegant, intuitive, attentive, accommodating, and entertaining. Lene is in the middle with the Dean of the Faculty of Science on the left and the Vice-Chancellor on the right.

Computer scientists from all over Denmark met for the second DIREC meeting at Helnan Hotel Marselis in Aarhus. As last time, the meeting included an excellent algorithms session, and this time Kevin Schewior gave a talk on Recent Advances in I.I.D. Prophet Inequalities. From our algorithms group, Kim Skak Larsen, Joan Boyar, Jakob Lykke Andersen, and Rolf Fagerberg also attended the meeting.

Kevin Schewior attended the Workshop on Approximation and Online Algorithms (WAOA) 2022. The workshop was part of ALGO 2022 in Potsdam, Germany, which had about 400 participants and several keynote speakers. Kevin gave a talk on Knapsack Secretary Through Boosting, a paper with his former Master's student Moritz Stinzendörfer (now TU Kaiserslautern), Andreas Abels (RWTH Aachen), and Leon Ladewig (formerly TU Munich), and chaired one of the sessions.

We are excited to welcome Casper Asbjørn Eriksen and Sissel Banke into our group as Ph.D. students. Both Casper and Sissel are CS MS graduates from our department and they will be working on Algorithmic Cheminformatics with their advisors, Jakob L. Andersen, Rolf Fagerberg, and Daniel Merkle.

We are excited to welcome Magnus Berg into our group as a Ph.D. student. He comes with an MS in mathematics and a side topic in computer science. Magnus will work on the project Online Algorithms with Predictions, as part of the national undertaking of Digital Research Centre Denmark (DIREC), under the Innovation Fund Denmark. The project is carried out in collaboration with ITU. As the main advisor, Kim Skak Larsen is joint by Lene Favrholdt and Melih Kandemir. Joan Boyar will also function as an advisor for the online part on equal terms with Kim and Lene, while Nutan Limaye from ITU and Melih will advise on connections to machine learning from different points of view.

Florian Hoersch is visiting the department this week from the Technische Universität Ilmenau, where also a former member of the group, Matthias Kriesell, is located. Hoersch's received his Ph.D. from the University of Grenoble in September 2021. His thesis contains a number of impressive results on graph connectivity and orientations of graphs. He will give a talk in the Computer Science colloquium series.

Yubao Guo from RWTH Aachen is visiting the department this week. Guo's Ph.D. thesis from 1995 focuses on locally semicomplete digraphs, a class of digraphs dicovered by Bang-Jensen in 1990 and since the topic of more than 100 research papers. Guo has made substantial contributions to the theory of locally semicomplete digraphs as well as semicomplete multipartite digraphs. Guo and Bang-Jensen have a number of joint papers together. Guo will give a talk in the Tuesday colloquium slot.

The Faculty of Science Teaching Prize is awarded each year to one employee who has excelled at motivational and committed teaching of the highest quality. In accordance with tradition, Lene Monrad Favrholdt was nominated by her students. Students say Lene is one of the best educators they have met, with an ability to make complex mathematical concepts easy to understand. Teaching math on the first year to students who don't know yet where and why they need it is a special challenge, and Lene is recognized for her enormous effort and focus on the students. During corona times, she made an extra effort of giving on-site lectures while arranging that students forced to stay home could also both follow and ask questions on-line. Lene is second from the left and the dean is speaking.

Rob van Stee from the University of Siegen visits the online algorithms group for a week. Rob is a friend of the department who has visited several times over the years, starting as a Ph.D. student. He has also served on thesis assessment committees for the department etc. Rob will give a talk in the Tuesday colloquium slot.

Bang-Jensen gave the talk Making a tournament k-strong by adding new arcs. This is based on joint work with Anders Yeo and former student Kasper Skov Johansen, now a research assistant at DTU Compute, starting his PhD studies there in the fall. At ICGT, Bang-Jensen also chaired the opening plenary talk by Reinhard Diestel.

While in Montpellier, Bang-Jensen visited his research collaborator, Stephane Bessy, at LIRMM Université Montpellier. They continued their long-term collaboration on the structure of directed graphs.

Lene Favrholdt, Joan Boyar, and Kim Skak Larsen attended SWAT 2022 - 18th Scandinavian Symposium and Workshops on Algorithm Theory, for the first time held physically in Tórshavn, Faroe Islands. Lene presented our joint paper, Joan chaired one of the sessions, and Kim leaned back and enjoyed the performances. ツ

Lene Favrholdt gave a keynote address on Paging and Packing with Possibly Precise Predictions at the 15th Workshop on Models and Algorithms for Planning and Scheduling (MAPSP) at the Oropa Sanctuary in Italy. At the same workshop, Kevin Schewior gave a contributed talk on The High-Dimensional Cow-Path Problem.

The chair of the program committee was Leah Epstein (U Haifa). The other keynote speakers were Alessandro Agnetis (U Siena), Thomas Erlebach (U Durham), and Alberto Marchetti-Spaccamela (La Sapienza). In total, there were more than 100 participants. MAPSP is known for a large number of high-quality talks but also its openness and the allotted time for discussions, e.g., during the social event, which in this case was a hike through meadows with cows to a mountain lake. Kirk Pruhs (U Pittsburgh) maintains a website on the history of the workshop.

We welcome Akbar Davoodi and Mehmet Aziz Yirik who join the Cheminformatics Group to work on the MATOMIC project. Akbar comes from a postdoc position at the Czech Academy of Sciences and Aziz finished his Ph.D. recently from the Friedrich-Schiller-University, Jena.

The MATOMIC project - Mathematical Modelling for Microbial Community Induced Metabolic Diseases - is launched through kick-off meetings at the National Institute of Public Health in Copenhagen today, and at SDU tomorrow. This internationally-based center is funded by the Challenge Programme of the Novo Nordisk Foundation and is headed by our Cheminformatics group: Daniel Merkle, flanked by Jakob Lykke Andersen and Rolf Fagerberg.

Kevin Schewior was invited to and attended the Workshop on New Challenges in Scheduling Theory in Aussois, France. The program committee consisted of Jacek Blazewicz (TU Poznan), Michael Bender (Stony Brook), Erwin Pesch (U Siegen), Kirk Pruhs (U Pittsburgh), Denis Trystam (Grenoble INP), and Guochan Zhang (Zhejiang U). The workshop had about 80 participants. A few of them attended online, but the vast majority attended on site. There were about 50 talks on the theory and practice of scheduling, many of which triggered refreshing in-person discussions during the ample time left free aside of the talks and during the cheese fondue. Kevin gave a talk about his recent work on Stochastic Probing with Increasing Precision.

Joan Boyar Lene Favrholdt, and Kim Skak Larsen were invited to the Workshop on Algorithms with Predictions, held at the Bernoulli Center for Fundamental Studies at EPFL in picturesque Lausanne, Switzerland. Joan and Lene gave a well-received invited talk together surveying Online Algorithms with Advice, and Kim was on the panel, together with Sid Banerjee (Cornell), Daniel Dadush (CWI), Anupam Gupta (Carnegie Mellon), and Seffi Naor (Technion), to discuss the current issues and priorities in this developing area. The workshop was very enjoyable with good talks and lots of time for networking and initiating research collaboration.

We are excited to welcome Kevin Schewior as assistant professor in the algorithms group. Kevin is interested in uncertainty, approximation algorithms, and algorithmic problems more generally. Kevin got his Ph.D. from the Faculty of Mathematics of Technische Universität Berlin in 2016. He has held postdoc positions in Germany but also in Santiago and Paris. We look forward to working with Kevin!

From our online algorithms group, Joan Boyar and Kim Skak Larsen joined the DDC meeting at Nyborg Strand Hotel, together with their Ph.D. student, Simon Skjernaa Erfurth. We enjoyed a well-planned and fruitful meeting, discussing the challenges that the Digital Democracy Center should undertake and the progress that has been made so far. The format of this 24 hour meeting, going from lunch to lunch, gave us the possibility of also interacting on a more social level in the evening, getting to know each other better.

We are excited to welcome Simon Erfurth into our group as a Ph.D. student. Simon comes with an MS in mathematics with a master's project in cryptology. He will work on the inter-disciplinary project, Trust and News Authenticity, as part of the Digital Democracy Center (DDC). Due to the inter-disciplinary nature of the project, Simon has several advisors, Claes de Vreese, who is the head of DDC, and Joan Boyar, Kim Skak Larsen, and Ruben Niederhagen from IMADA.

We are excited to welcome Yun Wang into our group as a Ph.D. student. Yun will continue work she startedinitiated while in China, under the guidance of her advisor, Jørgen Bang-Jensen, focusing on the project Structural and Algorithmic Properties Concerning Packing, Covering and Partitioning of Digraphs.

After such a long time with corona lockdowns and online meetings, it was great to meet in person with the many Danish computer scientists and the excellent algorithms people in particular. From our algorithms group, Kim Skak Larsen, Joan Boyar, Lene Favrholdt, Jakob Lykke Andersen, and Rolf Fagerberg joined the DIREC meeting at picturesque Nyborg Strand Hotel. The first day, the primary focus was on research, while the second day contained discussions related to student recruitment and retainment, diversity, societal needs, start-up companies, funding, etc.

Faith Ellen's student, Leqi "Jimmy" Zhu, wins the Principles of Distributed Computing Doctoral Dissertation Award, 2021, shared with one other graduate, for his dissertation On the Space Complexity of Colourless Tasks. The award will be presented to Jimmy at PODC on July 27.

The committee writes:

Zhu's thesis establishes general memory lower bounds for both deterministic and randomized algorithms for a variety of basic synchronization tasks including consensus, k-set agreement, and ε-approximate agreement. These bounds hold under a weak liveness assumption—obstruction-freedom—making them very general. Among the results in the thesis one stands out. It provides a definitive solution to a classic and long-standing open problem in distributed computing: to determine the space complexity of consensus in asynchronous, shared-memory systems. Besides the significance of the result, the committee also appreciated its beautiful execution—a clean, textbook-quality proof. On the basis of this achievement the committee made its decision to assign the award to this excellent piece of work.

Daniel Merkle, heading the Algorithmic Cheminformatic group, receives a grant of DKK 46.2 million from the Novo Nordisk Foundation Challenge Programme for the project Mathematical Modeling for Microbial Community Induced Metabolic Diseases (MATOMIC). This project will combine mathematical modelling and wet-lab experimentation to investigate how changing the composition of the microbiome can create a novel therapeutic tool for treating people with obesity.

Around 20 million of the grant goes to IMADA. The rest is shared by the project partners at the University of Leipzig, the University of Vienna, and the Helmholtz Centre for Environmental Research, Leipzig.

Faith Ellen's student, Leqi "Jimmy" Zhu, won the CS-Can|Info-Can Distinguished Dissertation Award, 2019, and has just given his talk in that connection.

In the talk, Jimmy discusses both his results without too many technical details and outlines his personal journey through his Ph.D. studies, pointing to people and circumstances of importance to him. Faith receives significant recognition of her rôle as his advisor.

Jimmy is now a postdoc at the University of Michigan.

David Hammer defends his Ph.D. dissertation under a cotutelle agreement, which will give him a Ph.D. degree from SDU (with Rolf Fagerberg as his advisor) as well as Goethe-Universität (with Ulrich Meyer as his advisor). The assessment committee consisted of Rasmus Pagh (IT University of Copenhagen), Peter Sanders (Karlsruher Institut für Technologie), Norbert Zeh (Dalhousie University), and the local chair, Kim Skak Larsen.

David gave a very nice presentation, Kim says, giving a good overview while also higlighting some of the deeper technical details required to establish his results. Congratulations to David, and to Rolf for having educated yet another excellent researcher.

Daniel Merkle takes over as head of the algorithms group from Kim Skak Larsen and enters into the department's management group at the same time. "Daniel will be a superb head of the group", Kim says, and continues: "I've known Daniel for more than 12 years, we share many of the same values, and I feel very comfortable with him leading this excellent research group."

Results on priority algorithms with advice, coauthored by Joan Boyar and Kim Skak Larsen got very good coverage at OLAWA - Online Algorithms with Advice and Related Models, a virtual satelite workshop of MFCS - the 45th International Symposium on Mathematical Foundations of Computer Science. Joan gave the talk on the second part of the paper.

Jørgen Bang-Jensen gave a 30 hour online course, followed by an exam, on directed graphs to more than 200 Chinese students at Shandong University. The course was very well received and has resulted in new collaborations, including a possible joint Ph.D. student.

For further information, see the local coverage at SDU, as well as the flattering feedback from Shandong.

Jørgen Bang-Jensen spend 4½ months on sabatical at INRIA Sophia Antipolis. Despite being locked down most of the time, due to Covid-19, he and his coauthors managed to produce 6 papers and lay the groundwork for a couple more.

The online algorithms group receives a grant from FNU for the project Online Algorithms with Machine Learning Predictors. The cheminformatics group receives a grant for the project Algorithmic Cheminformatics Meets Causality Analysis. We are excited to get started on these new directions of research.

Starting April 1, 2020, Faith Ellen has been appointed Adjunct Professor at SDU, where she will be associated with the Algorithms Group.

Faith Ellen received her Ph.D. from the University of California, Berkeley in 1982. Since 1995, she has been a full professor at the highly ranked Department of Computer Science at the University of Toronto. Among numerous awards and prestigious chairing appointments, she became a Fellow of the ACM in 2014, a very prestigious recognition from the community.

She has a strong connection to the group, having visited several times over the last two decades, and has joint work with professors Joan Boyar and Kim S. Larsen.

We are delighted to welcome Faith Ellen into our group.

Hesehus is an award-winning Odense-based IT company, specializing in e-commerce, so when CTO Martin Ehmsen expressed interest in a course on algorithms and efficiency for selected employees, the idea development was initiated by Professors Kim Skak Larsen and Rolf Fagerberg - both from IMADA's algorithms group.

"In the IT-world, the topics of algorithms and efficiency represent core competences with lasting value and relevance", says Rolf Fagerberg. It's topics he also teaches at the university, and he continues: "A course like this is a good and meaningful form of interaction between universities and companies", which was confirmed by the evaluation from the participants.

Hesehus has more than 120 employees and has repeatedly been honored in connection with the e-Commerce Prize, Børsen Gazelle, and with Great Place to Work.

The paper Fragile Complexity of Comparison-Based Algorithms by David Hammer, Rolf Fagerberg, and a group of international co-authors has received the Best Paper award at the 27th Annual European Symposium on Algorithms (ESA 2019), which is the premier European conference in algorithms. The paper studies the question of minimizing the number of comparisons that each individual element is subjected to in comparison-based algorithms, as opposed to the standard approach of minimizing the total number of comparisons. This question is motivated by settings where comparisons have some form of detrimental impact on the elements. Examples include comparisons between consumables such as beers, wine, apples, etc. (where each comparison consumes a part of the elements compared), sports matches (where the probability of injuries for a participant may grow with the number of matches taken part in), or ranking of documents (where bias or loss of confidentiality for a document may grow with the number of comparisons taken part in).

From February 1 through July 31, 2019, Daniel Merkle had a 6 month sabbatical as a visiting professor at the Harvard Medical School in the Fontana Lab at the Department of Systems Biology. The Harvard Medical School is ranked first among research-oriented medical schools in the 2020 rankings of the well-known "U.S. News and World Report". The two groups started joining forces and, among other things, in order to model chemistry are bringing their rule-based systems Kappa and MØD together.

The algorithms group was represented by Joan Boyar, Lene Favrholdt, Kim S. Larsen, and Rolf Fagerberg at HAlg - Highlights of Algorithms - that was held in Copenhagen this year. It is a relatively new meeting; only held for the fourth time this year. We were excited about the - for Computer Science - unusual format with 6 hour-long survey talks, a large number of invited talks, and a huge number of 4 minute talks that were combined with poster presentations. Among the many good talks, the online algorithms group (Joan, Lene, and Kim) was particularly fascinated with the survey talk on Learning in Algorithms, given by Sergei Vassilvitskii, where he discussed the combination of online algorithms and the use of machine learning in a setting similar to our recent work on advice complexity.

From May 25 through June 9, 2019, Professor Faith Ellen from the University of Toronto visited the group to work with Joan Boyar and Kim S. Larsen on competitive analysis in distributed algorithms. During her visit, she gave a wonderful survey talk on The Complexity of Consensus and Set Agreement.

TalentCampDK runs talent arrangements for selected elementary and high school students. Joan Boyar was invited to give the final address on Cryptology.

With Rolf Fagerberg as one of the organizers, the department welcomed 26 high schools students for IMADA's Computer Science Camp on March 2. This time it revolved around Deep Learning, in addition to career perspectives and glimpses of everyday-life for a Computer Scientist. On the photo, Caroline (an MS student of Kim S. Larsen) explains neural networks. Some students stayed overnight and participated in the Math Camp the following day. Lene Favrholdt taught on an extended version of this at the IT Camp for female high school students on March 30-31, where 25 girls were introduced to Python programming, user-driven app design, algorithms, big data, and AI.

Invited by Joan Boyar and Kim S. Larsen, Professor Ian Munro from the University of Waterloo, Canada, visited the group. Munro is a highly esteemed computer scientist, famous for his work on data structures in particular. During his stay, he gave the talk Fast Stable Sorting, Adapting to Existing Runs on the newest developments on the sorting problem.

In front of an audience of mathematicians and computer scientist in the Robert Schultz Lecture Theatre at the University of Manitoba, Joan Boyar gave a Pacific Institute for the Mathematical Sciences Distinguished Lecture with the title Multiplicative Complexity of Cryptographic Functions.

Two days earlier, she gave a colloquium talk in the Department of Computer Science on Complexity Classes for Online Algorithms via Advice Complexity.

Jørgen Bang-Jensen participates in a film project comprising ten 30 minute videos, where expert mathematicians present their research topics in a way that can be understood by final-year high school students. The aim of the videos and the accompanying material is to encourage more young people to study mathematically-oriented topics.

The Algorithms Group also likes meeting under less formal circumstances - here we are enjoying street food at Storms Pakhus.

Thomas Bellitto is hired as a postdoc in the Graph Theory Group from September 1, 2018 through February 29, 2020. Thomas obtained his Ph.D. degree from LaBRI, Université de Bordeaux in August 2018. Thomas will work with the group on problems related to packing, covering, and partitioning in (di)graphs.

Jørgen Bang-Jensen and Bjarne Toft organized the graph theory conference GT2018 at the picturesque location of Hotel Storebælt in Nyborg. There were 43 participants who came from as far away as South Africa, New Zealand, and Japan, enjoying the 32 presentations.

Joan Boyar and Kim S. Larsen attended WAOA - Workshop on Approximation and Online Algorithms at Aalto University School of Business. The workshop was a satellite workshop of ALGO. Joan gave a talk on joint work with Kim, Allan Borodin (University of Toronto), and Denis Pankratov (Concordia University) with the title Advice Complexity of Priority Algorithms. Kim contributed as session chair at the conference.

Anders Yeo, Marco Chiarandini, and student Steffan Leth Jensen visited Energinet in Fredericia where they gave the presentation Towards resilient networks: Detecting maximum imbalance after k links breakdown in the European electrical grid. This was the culmination of an individual study activity by Steffan, where he worked with Energinet on one of their practical problems.

This project will develop further into a master's project involving collaboration with Energinet.

Joan Boyar, Lene Favrholdt, and Kim S. Larsen attended MOLI - Modern Online Algorithms in the picturesque old Charles University in Prague. The workshop was a satellite workshop of ICALP. Joan gave a talk on joint work with Kim and Faith Ellen (University of Toronto) with the title The Scheduler is Very Powerful in Competitive Analysis of Distributed List Accessing and Lene gave the talk Upper and Lower Bound Techniques for Advice Complexity based on joint work with Joan and Kim, as well as former students Christian Kudahl and Jesper W. Mikkelsen. Several talks at the workshop cited results by our online algorithms group.

Jørgen Bang-Jensen and Gregory Gutin publish their third book on Classes of Directed Graphs (Springer, London). The book is an edited volume which, in addition to the four chapters authored by Bang-Jensen and Gutin, contains contributions from leading experts around the world.

Joan Boyar, Rolf Fagerberg, and Kim S. Larsen participated in SWAT - the Scandinavian Symposium and Workshops on Algorithm Theory in Malmö, June 18-20. Though this biannual conference is traditionally held in Scandinavia, it always presents a strong, international program. The conference is held in even-numbered years, whereas its sister conference, WADS is held in North America in odd-numbered year.

Joan and Kim were session chairs at the conference and Joan was on the program committee.

Joan Boyar, Rolf Fagerberg, Lene Favrholdt, David Hammer, and Daniel Merkle attended ARCO - the Algorithmic Research Cooperation around Oresund. Daniel talked about Graph Canonicalization Algorithms and their Application in Cheminformatics and David about Multi-way search trees of low height.

According to the ministerial order, a new corp of external examiners ("censor", in Danish) must be established every 4 years. After an application and screening process in cooperation with all Danish universities, the head of the national corp of external examiners, Kim S. Larsen announced the new corp today. In an international setting, using external examiners is quite unusual, but Kim thinks this adds to the quality of Danish university educations. In addition to preventing errors, it gives researchers a chance to exchange ideas and developments related to teaching across institutions, improving on topic selection in courses, and increasing the quality of teaching in general.

The last two days, 32 high school girls from all over Denmark spent the first two days of their Easter holidays learning about the two educations Computer Science and Software Engineering at SDU. The camp was organized in cooperation between the Faculty of Engineering and the Faculty of Science, in an effort to attract more women. Rolf Fagerberg was a driving force in the planning of the camp, and Lene Favrholdt held a workshop on Algorithms and Big Data. It was a great pleasure working with more than 30 enthusiastic girls, and the plan is to hold a similar camp again next year.

Kim S. Larsen enjoyed giving a talk on generally-applicable analysis techniques in online algorithms for the Theory Group in the Computer Science Department at the University of Toronto. It was an exquisite audience, including Allan Borodin, Joan Boyar, Stephen Cook, Faith Ellen, and Charles Rackoff, as well as a number of brilliant students. The overview part was based on joint work with many different coauthors over the years, while the core technical content was based on work with Joan Boyar, Lene M. Favrholdt, and Michal Kotrbčík, recently presented at WADS in St. John's, NL, Canada.

FNU granted the Online Algorithms group and Cheminformatics group, along with Fabrizio Montesi in Concurrency, 1,382,962 DKK to cover conference travel, research visits, and guests for the coming three years. Joan Boyar is PI of Online Algorithms and Cheminformatics Meet Concurrency. This time the success rate was around 12%.

On April 4, 2016, the algorithms group arranged the ARCO workshop — a small, informal, biannual meeting for algorithms researchers in the nearby geographic area, which includes parts of Denmark and Sweden.