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2026
08-20

Four Medals for the Switzerland at the International Olympiad in Informatics

The Swiss delegation received two Bronze and two Sliver medals at the 2026 International Olympiad in Informatics, which took place from August 9 to August 16 in Uzbekistan.

IOI 2026

Congratulations to Andrej Ševera and Laetitia Orglmeister for Silver, and Myriam Faltin and Yuhua Su for Bronze.

Tags

#SOI
2026
08-18

Congrats Jérôme!

Late 2022 / early 2023, when the GenAI hype started, one of the most obvious fields of application was immediately identified: education. And there surely are ways of, say, using tutoring systems that have potential to add value in complementing teachers. However, voices are now a little less enthusiastic and increasingly critical, addressing potential issues of using unrestricted vanilla LLMs. Today Jérôme Brender defended his dissertation under the supervision of Engin Bumbacher from HEP and Francesco Mondada from EPFL. I joined the committee together with Adrian Holzer from the Université de Neuchâtel and Ken Holstein from EPFL.

Jérôme Brender

Jérôme's work took a close look at the effects of unguarded LLM usage and what kind of scaffolds and features a tutoring system should implement in order to ensure what he calls reflective use of such systems. His work follows a clear thread and has been conducted in a real-world setting to investigate how LLM-based systems could actually increase learning gains through reflective LLM use.

In a sequence of sub-studies, he, for instance, compared Socratic guidance and prompt refinement, and developed a chatbot for peer discussions. This is important work, addressing one of the most pressing questions of our time: can GenAI be used in a meaningful and sustainable way to teach effectively? Jérôme's work provides some first answers, which give a very nuanced picture, and at the same time ask many important questions for follow-up work on the role of GenAI in education.

Tags

#Defense #Didactics
2026
07-29

Open Position within ABZ's Promotion of Gifted Students

The Center for Computer Science Education (ABZ, “Ausbildungs- und Beratungszentrum für Informatik­unterricht”) is very active in the promotion of gifted students. We are currently extending our program to contain teaching material and lessons on robotics and artificial intelligence. To this end, we are looking for someone to support us with designing and testing the material.

Open position at ABZ

The position is 40% and funded for one year, starting late 2026.

If you are interested, you may consider sending a cover letter and your CV to Elizabeta Cavar until September 15, 2026.

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#ABZ #Hiring
2026
07-12

Girls Training for the European Girls' Olympiad in Informatics

Swiss Olympiads in Informatics LogoAlso this year, the Swiss Olympiad in Informatics (SOI) organizes a training camp for girls to prepare for this year's competition. The camp will take place in Zurich from September 5 to September 11. It is free of charge and open to all females who have some basic programming experience; no advanced knowledge of algorithms is assumed.

This is a fantastic event, tell your daughters, tell your students, and spread the word.

Tags

#SOI
2026
07-05

The fifth Edition of the Swiss Informatikbiber

Starting in 2022, for the fifth time now, we organized the finals of the Swiss edition of the “Informatikbiber” competition (Bebras) in parallel with the STIU at ETH. Just like the four times before, this was a very humbling experience to be part of, and I always get caught somewhat off guard by the proud kids and the prouder parents.

In particular, in times when machines appear to be more and more capable of taking over problem-solving tasks, we have to make sure that the corresponding skill set is part of education. The “Informatikbiber” is not an isolated event; CS teachers actively motivate and prepare their students, and we should be thankful to each and every one of them. The competences they foster will be of ever more importance in the future. A future that will be built by these students.

Informatikbiber 2026

Congratulations to all the finalists and winners of this year!

Tags

#ABZ #Informatikbiber #STIU
2026
06-10

Congrats Marko!

As a theory person, who decided to branch out into CS Education, I had to learn over the years that I am much less of a rare exception than I thought. Theory people generally seem to care about teaching. Yesterday I visited Thomas Zeume's group at RUB in Bochum to join the examination committee of his doctoral student Marko Schmellenkamp, teaming up with Jan Vahrenhold.

Marko Schmellenkamp

Marko's thesis covers research from both Theory of Computing and CS Education and is truly interdisciplinary in nature—together with his colleagues implementing a tool, the ILTIS platform, informed by research in both fields. In essence, Marko investigated misconceptions and typical errors made by students when studying topics from computability and complexity theory as encountered in typical undergraduate Theory courses. The insights are then implemented in ILTIS, which can be used by students to practice central Theory topics, providing feedback on their solutions.

The challenging part here is that, say, checking whether a student-generated context-free grammar is equivalent to a desired solution is in fact undecidable. Marko came up with some very clever concepts that allow a large fraction of student solutions to be checked automatically, flagging only a small number for human review.

This is just one contribution, and I am happy to see that ILTIS is by now used in a large number of Theory courses.

Tags

#Defense #Theory #Didactics
2026
05-04

Tokenization is NP-Hard Even When Considering Smallest Possible Alphabets

ICLR 2026 One of the first things we teach in highschool CS are number representations. Students should get a good idea of how numbers can be represented before diving into topics like error-correcting codes, compression, cryptography, or even algorithm design. Probably the best access to the idea of presenting a number with respect to some base was already presented in the textbooks of Juraj Hromkovič for primary school students: coin systems.

There is an interesting piece of history here in that almost all coin systems that ever existed and exist are canonical, which means that they have the property that, for any price x you want to pay, a simple greedy approach results in the smallest possible number of coins to use: take the largest coin of value at most x as often as possible; continue with the second-largest coin of value at most x; and so on. One can come up with some coin system for which this is not the case. (You may want to pause and think about one; three coin types suffice.) As a matter of fact, people did, for instance, when designing the British pre-decimal coin system (which was used until 1971) and which contained denominations (coin types) 1/2, 1, 3, 6, 12, 24, 30, 60, and 240. If you want to pay a price of, say, 48, the greedy approach takes one coin of value 30, then one of value 16, and then one of value 2, while there is an optimal solution that uses two coins of value 24.

How full of joy I was to find out (well, being told by my student Philip Whittington, that is) that this problem is actually very closely connected to a very important one in the large-language-model pipeline: Tokenization is the problem of defining a set of tokens (the smallest units on which to work on in what follows) that can be used to represent a given text over characters in, say, a way that is compressed best possible.

Using some beautiful gadgets and reductions—just like in the good old days—, Philip, Violeta Kastreva (who was visiting our group as part of the ETH Summer School Research fellowship program, SSRF), Tiago Pimentel, and I were able to show that different variants of this problem are APX-hard, even if we only consider binary alphabets over which the original strings are defined. If the alphabet is unary, the problem is still NP-hard. And exactly this problem corresponds to computing a best coin system.

Tags

#Theory
2026
04-30

Swiss Day for Computer Science Education 2026

STIU 2026I am happy to share that registration is now open for the 15th Swiss Day for Computer Science Education (“Schweizer Tag für Informatik­unterricht,” STIU), taking place on June 19 at ETH. Note that this is a Friday this year.

STIU 2026

This year's edition will feature 11 workshops for prospect or in-service teachers, or anyone else who is interested in teaching Computer Science in K-12. Topics covered include programming education, STEAM, unplugged activities, cybersecurity, and artificial intelligence.

I am honored to welcome our special guests Andreas Bollin and Roderick Bloem from Austria, who played a pivotal role in establishing the new subject "Informatik und künstliche Intelligenz," and Michael E. Caspersen from Denmark, where 51 pilot schools (and thus 280 classes) will integrate CS into their curricula.

For the fifth time, the finals of the Swiss CS Beaver Competition together with the award ceremonies will be a part of STIU, and we will award the rector's STEM prize and the ABZ medal of honor to individuals and institutions that have made a special contribution to sustainable computer science education.

Photo of Computer Science Beaver Participants

I am looking forward to welcoming you at STIU 2026 in a little more than one and a half months.

Tags

#ABZ #Informatikbiber #STIU
2026
03-31

A Monthly “Stammtisch” for Zurich Computer Science Teachers

Are you a Computer Science teacher in the greater Zurich area, looking for peers to talk about your lessons, Computer Science education in general, to get inspiration on how to teach a certain topic, or simply to expand your network?

Of course you are! Then I am happy to point you to a fantastic initiative of two of our former students, Rob Branchat and Patric Rousselot, who organize a monthly get-together (“Stammtisch”) in central Zurich. The dates are already fixed and announced for May through August, and a registration would be welcome to make planning easier. I will, of course, try to show up on some of these dates.

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It indeed seems that recently at least some parts of Computer Science education are becoming a fast-moving target. Large Language Models, interdisciplinarity, potential focus subjects, and so many other topics pose questions to which no one knows all the answers. Let us try to approach them together; in an informal setting, with a cold beverage.

Tags

#Lehrdiplom
2026
02-28

The “Informatiktage 2026” and a Long-Overdue Addition to WebTigerPython

This year's “Informatiktage” will take place from March 16 to March 21 and feature three ABZ workshops, all dedicated to programming education. As last year, Joël Lindegger will offer a creative way into coding with XLogoOnline–this time focussing on adults, who maybe want to get a glimpse of what their kids are doing in primary school (or so I hope).

Clemens Bachmann will introduce a new WebTigerPython feature implemented by Joël and him, namely a browser-based implementation of GameGrid, with two workshops aimed and students and their teachers, respectively. The original GameGrid was written in Java and very popular among teachers as it allows a comprehensive introduction to object-oriented programming. Of course, simply porting such a Java library with all its asynchronicity to run in the browser is far from trivial, which is why it had to be rewritten from scratch and uses PyGame under the hood.

Example of a game built in WebTigerPython with GameGrid

WebTigerPython now supports a majority of the PyGame features, with more to come. Actually, if you have any particular feature requests, please let us know.

Tags

#ABZ #Informatiktage #TigerPython #XLogoOnline
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