Mikołaj Bojańczyk

2017/2018

## Algebraic language theory (automaty a półgrupy)

This course is about an alternative approach to regular languages, where one uses monoids (and more fancy algebraic structures) instead of automata.  I use notes from this lecture, but I hope to create a new version in pdf for this one (this has not materialised, I'm sorry). Lecture: Fridays 14:15-15:45 (room 4060) Exercises: Fridays 16:00-17:30 (room 4060) Exam The exam is oral. Here are the topic and some materials for them.
1. Monoids and Green's relations
2. Factorisation forests
3. First-order logic and LTL
4. Omega and scattered words
5. Countable words
7. What is an algebra for graphs and Courcelle's Theorem (also sections 3 and 4  here)
8. Recognisability implies definability for bounded treewidth (these and these slides, also this paper if you reallly must)
Please email me to choose a time.  Choose any subset of the 8 topics in the list above, here is the exchange rate: • 3 topics: dostateczny • 4 topics: dobry • 6 topics: bardzo dobry

## Advanced Topics in Automata 2017/2018 (Języki, Automaty i Obliczenia 2)

This lecture is a choice of slightly more advanced topics from automata theory. The lecture is on Tuesdays, 12:15 in room 5820. The exercises are on Wednesdays, 16:15 in room 5820, with Wojciech Czerwiński. Here is a plan of the lecture. There was a similar lecture last year and the year before that. This year we use lecture notes in pdf (some topics in the notes will not be covered by the lecture, and will not be on the exam). Here is the current version:

If you find a mistake (or something not clear, or something you can do better, etc.) in the notes, please put it here. Every mistake (for the first person to find it) increases your grade, with .02 for typos,  .05 for small errors, and bigger values for bigger or more subtle mistakes.

Exam. The exam is an oral exam, which is mainly questions about the proofs of theorems. Please email me to choose a time, or better use this spreadsheet .You can improve your exam grade using the star exercises.  Choose any subset of the 8 topics in the list below, here is the exchange rate: • 2 topics: dostateczny • 3 topics: dobry • 4 topics: bardzo dobry
1. Determinisation of $\omega$-automata
2. Infinite duration games • Parity games in quasipolynomial time
3. Tree-walking automata
4. Distance automata • Vector Addition Systems
5. Weighted automata over a field
6. Decidability of the first-order theory of (R,+,*) no notes for this!
7. Polynomial grammars
8. Parsing in matrix multiplication time • Learning automata

2016/2017

## Advanced Topics in Automata 2016/2017 (Języki, Automaty i Obliczenia 2)

This lecture is a choice of slightly more advanced topics from automata theory. The lecture is on Tuesdays, 12:15 in room 5820. The exercises are on Wednesdays, 16:15 in room 5820, with Wojciech Czerwiński. Here is a plan of the lecture. There was a similar lecture last year. Here are the topics for this year: Exam. The exam is an oral exam, which is mainly questions about the proofs of theorems. Please email me to choose a time. You can improve your exam grade using the star exercises.  Choose any subset of the 6 topics in the list above, here is the exchange rate: • 2 topics: dostateczny • 3 topics: dobry • 4 topics: bardzo dobry

## Infinite alphabets

This is a lecture on automata (and later other devices) that operate on infinite alphabets. The lecture is on Wednesdays at 12:15 in room 4060. The exercises are on Mondays at 14:15 in room 5050. The lecture and exercises are shared by Mikołaj Bojańczyk and Sławomir Lasota. Lecture notes Homework assignments Exam
Here is an overview of the course Data words and their automata In the first half of the lecture, we discuss some concrete models, typically involving registers. The emptiness problem for most powerful of the models, data automata, will as hard as the famous reachability problem for vector addition systems, and the lecture will contain a description of the latter.
1. Introduction to automata with registers
2. Alternating automata with registers
3. Data automata
4. Logic on data words
5. Reachability for vector addition systems
Sets with atoms In the second part of the lecture, we move to a more general setting, which describes some of the previous constructions in a cleaner mathematical model. This mathematical model will lead us to discover new questions.
1. Sets with atoms and orbit-finiteness
2. Automata in sets with atoms
3. Atoms with structure other than equality
4. Oligomorphism
5. What is a computable function?
6. Turing machines with atoms

Lipa

## Lipa summer school 2017 (Warsaw, July 3-6)

The Lipa Summer School is a school on topics connected to logic in computer science. It is part of this grant. It was held in Warsaw, July 3-6 2017.  The school had 4 mini-courses given by:
• Stephan Kreutzer (Berlin) Algorithmic meta-theorems (videos: 1, 2, 3, 4)
• Joël Ouaknine (Saarbrücken) Decision Problems for Linear Recurrence Sequences (videos: 1234)
• Moshe Vardi (Rice)  Linear-time verification and synthesis  (videos: 1234)
• Mikołaj Bojańczyk (Warsaw, organiser) What is a recognisable language? (videos: 1234)
Each mini-course was 6 hours long (4 x 90 minutes). Here is the programme. Registration is closed. There will be free lunch and coffee breaks for registered participants, but not dinner (we will do an informal picnic on some evening without rain). The school is followed by ICALP.

## Dates

• May 30 Registration with request for student accommodation
• June 20 Registration without request for student accommodation
• July 3-6 School

## Local information

The school was held at the University of Warsaw, in the Center of New Technologies, whose address is Banacha 2c. Be careful about the map on the Center's page, it's wrong, use the one below.   Picture of the conference venue and map below   A taxi from the airport should be around ≤ 20 PLN during the day (the official taxi queue is when you leave the airport, don't go with the people who whisper "taxi, taxi"). Here is a link for accessing the school from the airport using public transport (bus 175 or 188).
The school is part of the grant Lipa that has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement No 683080).

## Lipa Summer School 2018 (June 25-28)

The Lipa Summer School is a school on topics connected to logic in computer science. It is part of this grant. This is the second edition, the first one was in 2017 (there are videos).  It will be held in Warsaw, June 25-28 2018.  The school consists of 4 mini-courses given by: Each mini-course is 6 hours long (4 x 90 minutes). Here is the program. Click on the talk titles to get descriptions and slides. There will be videos, but a few months after the school is over. Registration is free, and we might have a limited number of student dormitories for free.  We will likely (depending on the number of registrations) have  free lunch and coffee breaks for registered participants, but no dinner (we will do an informal picnic on some evening without rain).

## Dates

• May 15 End of registration with request for student accommodation
• June 15 End of registration without request for student accommodation
• June 25-28 School

## Venue

The school will be held in (room C of the) Auditorium Maximum of the university of Warsaw, in the historical center of Warsaw. Here is the building: Here is a map:
The school is part of the grant Lipa that has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement No 683080).

2015/2016

## Algebraic Language Theory

The general theme is monoids instead of automata. We will go deep (e.g. on the structure of finite monoids) and wide (on "monoids" for infinite words etc.)

Lecture: Thursday 12:15 – 13:45  (room 3170) Exercise: Thursday 14:15 – 15:45 (room 3170)

I will use the notes from my previous course, but modified.

## Advanced Topics in Automata (Języki, Automaty i Obliczenia 2)

This lecture is a choice of slightly more advanced topics from automata theory. The lecture is on Tuesdays, 12:15 in room 5070. The exercises are on Wednesdays, 16:15 in in room 5820, with Wojciech Czerwiński. Here are the star exercises and their solvers. Exam. The exam is an oral exam. Please email me to choose a time or use this link for Feb 15. Choose any subset of the 9 topics in the list above, here is the exchange rate: • 3 topics: dostateczny • 5 topics: dobry • 7 topics: bardzo dobry

2014/2015

## Algebraic Language Theory

This course is about an alternative approach to regular languages, where one uses monoids or semigroups instead of automata. Lecture: Tuesdays 8:45-10:15 (room 5070) Exercises: Tuesdays 10:25-11:55 (room 5070)

## Języki, automaty i obliczenia

Ćwiczenia do wykładów Sławomira Lasoty oraz Wojciecha Ryttera.

2013/2014

2011/2012

2009/2010