Young Topologists Meeting 2026

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University of Copenhagen
29 June - 3 July, 2026

The booklet with the detailed schedule and abstracts of the contributed talks (last updated 26.6.26).

Lecture notes for Achim Krause's talks.

 

There will be contributed talks by participants as well as two lecture series by:

  • Luciana Basualdo Bonatto (University of Oxford)

Title: Mapping class groups, operads, and Grothendieck–Teichmüller theory

Abstract: Grothendieck–Teichmüller theory uses geometric and topological objects to shed light on one of the most mysterious structures in number theory: the absolute Galois group of the rationals. At its core, this theory suggests that we should build a tower of mapping class groups, whose symmetries are expected to encode this Galois group. In this lecture series, we will develop the main ideas and tools that enter modern topological approaches to Grothendieck–Teichmüller theory.

We will begin with an overview of mapping class groups and some of the key geometric techniques used to study them. We will then introduce operads and modular operads as a framework for organizing gluing operations and compatibility conditions, explaining how a dendroidal viewpoint provides both motivation and structure. Finally, we will bring these ideas together in the construction of a Teichmüller tower as a modular operad of mapping class groups, equipped with an action of the absolute Galois group of Q.

  • Achim Krause (University of Oslo):

Title: Perspectives on spectra

Abstract: In these lectures, I want to explore some modern perspectives on spectra and stable homotopy theory. After reviewing several perspectives on the category of spectra, we will consider several ways in which spectra can be "controlled through algebra", culminating in the machinery of synthetic spectra and a very elegant proof of the Nilpotence Theorem due to Burklund. In the final lecture, I want to outline an ongoing project with Ben Antieau we refer to as "effective spectra", which follows a somewhat different angle on the "control spectra through algebra" theme.

 

 

 

 

 

 

 

Time Mo Tue Wed Thu Fri
08:30-09:15 Registration
09:15-09:30 Opening
09:30-10:30 Krause 1 Basualdo Bonatto 1 Krause 2 Basualdo Bonatto 3
11:00-11:30 Talk 1a/Talk 1b Talk 7a/Talk 7b Talk 9a/Talk 9b Krause 3 Talk 19a/Talk 19b
11:35-12:05 Talk 2a/Talk 2b Talk 8a/Talk 8b Talk 10a/Talk 10b Talk 20a/Talk 20b
12:05-13:30 Lunch Lunch Lunch Lunch Closing + Lunch
13:30-14:00 Talk 3a/Talk 3b Social events

Basualdo Bonatto 2

 Talk 15a/Talk 15b
14:05-14:35 Talk 4a/Talk 4b Talk 16a/Talk 16b
14:35-15:15 Pastries Pastries Pastries
15:15-15:45 Talk 5a/Talk 5b Talk 11a/Talk 11b Talk 17a/Talk 17b
15:50-16:20 Talk 6a/Talk 6b Talk 12a/Talk 12b Talk 18a/Talk 18b
16:20-16:45 Break
16:45-17:15 Talk 13a/Talk 13b
17:20-17:50 Talk 14a/Talk 14b
Evening Posters and Pizza Dinner

The conference dinner will begin at 7:00PM at Foodclub Nørrebro. For anyone interested, we can meet at 6:30 PM in front of the building and walk to the restaurant all together.

 

 

 

 

 

 

 

 

 

 

The conference/masterclass will take place at the Department of Mathematical Sciences, University of Copenhagen. See detailed instructions on how to reach Copenhagen and the conference venue.

Tickets and passes for public transportation can be bought at the Copenhagen Airport and every train or metro station. You can find the DSB ticket office on your right-hand side as soon as you come out of the arrival area of the airport. DSB has an agreement with 7-Eleven, so many of their shops double as selling points for public transportation.

A journey planner in English is available.

More information on the "find us" webpage.

 

 

 

 

 

 

We can only provide accomodation for some contributed speakers and poster presenters. We kindly ask the other participants to organise their own accomodation.

We recommend Hotel 9 Små Hjem, which is pleasant and inexpensive and offers rooms with a kitchen. Other inexpensive alternatives are Steel House Copenhagen (close to city centre), and CabInn, which has several locations in Copenhagen: the Hotel City (close to Tivoli), Hotel Scandinavia (Frederiksberg, close to the lakes), and Hotel Express (Frederiksberg) are the most convenient locations; the latter two are 2.5-3 km from the math department. Somewhat more expensive – and still recommended – options are Hotel Nora and  Ibsen's Hotel.

An additional option is to combine a stay at the CabInn Metro Hotel with a pass for Copenhagen public transportation (efficient and reliable). See information about tickets & prices.

 

 

 

 

 

 

 

 

 

 

 

 

Registration is closed.

In case you need a confirmation of registration for visa purposes please contact Jan Tapdrup.

 

 

 

 

 

 

 

 

 

 

Organisers:

Omer Bojan (omer.bojan "at" math.ku.dk)

Jonathan Clivio (jocl "at" math.ku.dk)

Jan Ole Hesse (jan.hesse "at" math.ku.dk)

Chenglong Ma (chenglong.ma "at" math.ku.dk)

Isaac Moselle (ismo "at" math.ku.dk)

Florian Riedel (fmr "at" math.ku.dk)

Semen Slobodianiuk (semen.slobodianiuk "at" math.ku.dk)

Robert Szafarczyk (rs "at" math.ku.dk)

Philippe Vollmuth (pvv "at" math.ku.dk)

Admin:

Jan Tapdrup (jt "at" math.ku.dk)