## Jun.-Prof. Dr. Caroline Lassueur

**Juniorprofessur für Darstellungstheorie (Junior Professorship for Representation Theory)**

→ Part of the Research Group Representation Theory lead by Prof. Dr. Gunter Malle.

→ Member of the DFG SFB-TRR 195 "Symbolic Tools in Mathematics and their Application".

**Links:**

ORCiD, arXiv, MathSciNet, zbMATH , MGP , GoogleScholar

**Co-authors:**Bernhard Böhmler, Niamh Farrell, Gerhard Hiß, Shigeo Koshitani, Gunter Malle, Nadia Mazza, John Murray, Benjamin Sambale, Elisabeth Schulte, Jacques Thévenaz

**Recent/Upcoming Events:**

**Sept 2024**: I am co-organising the**Meeting***Representation Theory at the Villa Denis 2024***2nd of July 2024**:**Felix-Klein-Colloquium talk**by Pierre-Emmanuel Caprace**June 2024**:**Sam Miller**is visiting our working group**8th of June**: Tag der Mathematik 2024 at the RPTU in Kaiserslautern**May 2024**: 1st in the Women's Team Ranking with the Team RPTU at the**B2Run Firmenlauf 2024****Feb 2024**: I was at the*Darstellungstheorietage 2023 (!!)***Dec 2023**: I was at the*Nikolaus Conference 2023***Oct 2023**: I co-organised the**meeting***Representation Theory at the Villa Denis 2023***WS 2023/24: On leave for the purpose of a Substitute Professorship at the Leibniz Universität Hannover****Sep 2023**: Bernhard Böhmler defended his doctoral thesis successfully

**Selected Recent/Upcoming talks**:

**Jul 2024**: Ringvorlesung, RPTU Kaiserslautern-Landau**Jan 2024**: Oberseminar zur Algebra und Algebraischen Kombinatorik, Leibniz Universität Hannover**Sep 2023**: Algebra and Number Theory in Conversation, University of Manchester**Apr 23**: Meeting Representation Theory of Finite Groups at the MFO

**Previous Events [+]**

**Academic year 2022-2023**

**Jul 2023**: John Murray is visiting us**Jun 2023**: Shigeo Koshitani is visiting us**Apr 2023**: Workshop Representations of Finite Groups at the MFO.**7th Feb 2023**: Kathryn Hess Bellwald is invited to talk in the*Felix-Klein-Kolloquium***Feb 2023**: talk at Algebra Seminars at Bilkent University**Feb 2023**: talk at the Colloque tournant du GDR TLAG, Université de Reims (FR)**Dec 2022**: talk at the Seminars in Algebra at Mindanao State University - Iligan Institute of Technology (MSU-IIT)**Dec 2022**: talk at the Nikolauskonferenz 2022, RWTH Aachen**Nov 2022**: Gerhard Hiss is visiting us.**Oct 2022**: The*Representation Theory Days 2022*took place at the TU Kaiserslautern**Sept 2022**:*Representation Theory at the Villa Denis 2022***Sept 2022**: talk at the 2nd SFB/TRR 195 Annual Meeting, Tübingen**Sept 2022**: Invited Summer School Lecture Modular Representation Theory of Finite Groups at the IKIU Summer School on group representation theory [**Lecture Notes and Handouts**]

**Academic year 2021-2022**

**Aug 2022**: Talk at the Workshop Structure of Group Algebras over Local Rings, Ambleside (UK)**July 2022**: Michael Geline is visiting us.**Jun 2022**: Talk at Techniques fonctorielles en théorie des groups, Amiens**[SLIDES]****May/Jul 2022**: Programme Participant in the Programme Groups, Representations, and Applications: New Perspectives held at the Newton Institute, Cambridge.**Apr-Jun 2022**: Guest seminar "Gruppen und Darstellungen" in presence in Kaiserslautern**Jan/Feb 2022**: Guest seminar Kaiserslautern-Aachen "Gruppen und Darstellungen" with a series of 8 virtual talks

**Academic year 2020-2021**

**Dec 2021**: We organise the*Darstellungstheorietage*directly followed by the*Nikolaus Conference*at the RWTH Aachen.**Winter semester 20/21**: ON LEAVE for the purpose of an interim professorship for Algebra und Number Theory at the RWTH Aachen University**September 2021**: Summer School Lecture "Introduction to the Modular Representation Theory of Finite Groups" at the Young Algebraists´ Conference 2021**Winter semester 20/21**Bernhard Böhmler is visiting Robert Boltje at UC Santa Cruz with a DAAD fellowship for doctoral students.

**Older academic events**

**July 2021**: Two Days of Representation Theory at the Villa Denis [Photos].**Apr-Jun 2021**: 8 virtual talks scheduled in our guest seminar "Gruppen und Darstellungen"**March 2021**: two-week research stay at the MFO. Oberwolfach Research Fellowship obtained together with Niamh Farrell.**Jan/Feb 2021**: our guest seminar "Gruppen und Darstellungen" starts again with a series of 6 virtual talks**December 2020**: Talk at the Virtual Nikolaus Conference 2020**September 2020**: Two Days of Representation Theory at the Villa Denis. [Pictures]**April 2020**: the*Felix-Klein-Kolloquium Talk by Kathryn Hess Bellwald*is postponed**June 2020**: 10 years ago...- Jan-May 2020: Research Semester
Groups, representations and applications: new perspectives at the Newton Institute in Cambridge **Oct 2019**: Representation Theory at the Villa Denis 2019**Nov 2019**: Shigeo Koshitani is visiting us**Dec 2019**: Nikolauskonferenz 2019, RWTH Aachen**Dec 2019**: Women in algebra and symbolic computations**Dec 2019**: Robert Boltje is visiting us

### Publications and Preprints [+]

**In progress.**

*On the source algebra equivalence class of blocks with cyclic defect groups, Part II*,

(with G. Hiß)

**Submitted.**

*The self-dual indecomposable modules in blocks with cyclic defect groups*,

(with J. Murray)

[arXiv]*Trivial source character tables of Frobenius groups of type \((C_p\times C_p)\rtimes H\)*,

(with B. Böhmler)

[arXiv]

**Accepted.**

*Principal \(2\)-blocks with wreathed defect groups up to splendid Morita equivalence*,

(with S. Koshitani and B. Sambale)

To appear in: Annals of representation Theory

[arXiv]

**Published.**

*On the source algebra equivalence class of blocks with cyclic defect groups, Part I*,

(with G. Hiß)

Beitr. Algebra Geom.**65**(2024), 187-207. [doi | arXiv | Preprint]*A tour of \(p\)-permutation modules and related classes of modules*,

Jahresber. Dtsch. Math.-Ver.**125**(2023), 137-189. [doi | preprint]*Trivial source character tables of \(SL_2(q)\), Part II*,

(with N. Farrell)

Proc. Edinburgh Math. Soc.**66**(2023), 689-709. [doi | arXiv]*Trivial source endo-trivial modules for groups with semi-dihedral Sylow 2-subgroups*,

(with S. Koshitani)

Beitr. Algebra Geom.**66**(2022), 233–246. [doi | arXiv | preprint]*Trivial source character tables of \(SL_2(q)\), Part I*,

(with B. Böhmler and N. Farrell)

J. Algebra**598**(2022), 308-350. [doi | arXiv | Oberwolfach Preprint]*Splendid Morita equivalences for principal blocks with semi-dihedral defect groups*,

(with S. Koshitani and B. Sambale)

Proc. Amer. Math. Soc.**150**(2022), 41-53. [doi |arXiv | preprint]*The classification of the trivial source modules in blocks with cyclic defect groups*,

(with G. Hiß)

Algebr. Represent. Theory**24**(2021), 673–698. [doi | arXiv | Preprint]*Trivial source characters in blocks with cyclic defect groups*,

(with S. Koshitani)

J. Algebra**574**(2021), 375-408. [doi | arXiv | preprint]*Splendid Morita equivalences for principal \(2\)-blocks with generalised quaternion defect groups,*

(with S. Koshitani)

J. Algebra**558**(2020), 523-533. Special issue in honour of Michel Broué. [doi | arXiv | Preprint]*Splendid Morita equivalences for principal \(2\)-blocks with dihedral defect groups*,

(with S. Koshitani)

Math. Z.**294**(2020), 639–666. [doi | arXiv | Preprint]*Simple modules in the Auslander-Reiten quiver of principal blocks with abelian defect groups*,

(with S. Koshitani)

Nagoya Math. J.**235**(2019), 58–85. [doi | arXiv | .pdf]*On the lifting of the Dade group,*

(with J. Thévenaz)

J. Group Theory**22**(2019), 441–451. [doi | arXiv | infoscience]*Lifting endo-\(p\)-permutation modules*,

(with J. Thévenaz)

Archiv Math.**110**(2018), 205–212 [doi | arXiv | .pdf]*Endo-trivial modules: a reduction to \(p'\)-central extensions*,

(with J. Thévenaz)

Pacific J. Math.**287**(2017), 423–438. [doi | infoscience]*Universal \(p'\)-central extensions*,

(with J. Thévenaz)

Expo. Math.**35**(2017), 237–251 [doi | infoscience | .pdf]*Endo-trivial modules for finite groups with dihedral Sylow 2-subgroups*

(with S. Koshitani)

J. Group Theory**19**(2016), 635–660. [doi | arXiv]*Simple endotrivial modules for quasi-simple groups*,

(with G. Malle and E. Schulte)

J. reine angew. Math.**712**(2016), 141–174. [doi | arXiv | .dvi]*Endotrivial modules for the Schur covers of the symmetric and alternating groups*,

(with N. Mazza)

Algebr. Represent. Theory.**18**(2015), 1321-1335. [doi | arXiv]*Simple endotrivial modules for the linear, unitary and exceptional groups*,

(with G. Malle)

Math. Z.**280**(2015),1047–1074. [doi | arXiv]*Endo-trivial modules for finite groups with Klein-four Sylow 2-subgroups*,

(with S. Koshitani)

Manuscripta Math.**148**(2015),265–282. [doi | arXiv]*Endotrivial modules for the sporadic groups and their covers*,

(with N. Mazza)

J. Pure Appl. Algebra.**219**(2015), 4203–4228. [doi | arXiv | .pdf]*Endo-\(p\)-permutation modules and relative endotrivial modules in the Auslander-Reiten quiver*,

J. Algebra**420**(2014), 1–14. [doi]*The Dade group of a finite group*,

J. Pure Appl. Algebra**217**(2013), 97–113. [doi | infoscience | .pdf]*Relative projectivity and relative endotrivial modules*,

J. Algebra, Vol.**337**(2011), 285–317. [doi | infoscience | .pdf]

**Other Documents:**

*On the source-algebra equivalence class of blocks with cyclic defect groups*, Oberwolfach Rep.**19**(2023), Representations of Finite Groups 2023 [doi]*Trivial source character tables of \(SL_2(q)\)*,

(with B. Böhmler and N. Farrell), Oberwolfach Preprint*On the Lifting of the Dade group and Consequences*, Oberwolfach Rep.**16**(2019), Meeting Representations of Finite Groups [doi]*Reading endo-trivial modules from the Brauer tree*, RIMS Kôkyûroku No. 1926. Proceedings of the Symposium*Research on Finite Groups and their Representations, Vertex Operator Algebras, and Algebraic Combinatorics*, March 2014. [www]

**Theses:**

*Relative Projectivity and Relative Endo-trivial Modules*, Doctoral Thesis

[Thèse EPFL no 5266 | DOI:10.5075/epfl-thesis-5266 | infoscience | .pdf]

Private Defence: 09.12.2011, Public Defence: 23.03.2012 [Invitation]*The \(p\)-local splitting of the infinite complex projective space and co-H-structures*, Master Thesis, Mar. 2007, Supervision: Prof. Dr. Birgit Richter (Universität Hamburg) [.pdf / poster]

### Talks [+]

**Places where I gave talks**

**2024:**

- Ringvorlesung, RPTU Kaiserslautern-Landau, Jul 2024
- Oberseminar zur Algebra und Algebraischen Kombinatorik, Leibniz Universität Hannover, Jan 2024

**2023:**

- Algebra and Number Theory in Conversation, University of Manchester, Sep 2023
- Meeting Representation Theory of Finite Groups at the MFO, Apr 2023
- Algebra Seminars at Bilkent University, Feb 2023
- Colloque tournant du GDR TLAG, Université de Reims (FR), Feb 2023

**2022:**

- Seminars in Algebra, Mindanao State University, Iligan Institute of Technology, Dec 2022
- Nikolauskonferenz 2022, RWTH Aachen, Dec 2022
- Representation Theory at the Villa Denis 2022, TU Kaiserslautern, Sept 2022
- 2nd annual meeting of the DFG SFB-TRR 195, Tübingen, Sept. 2022
- Summer School on the Representation Theory of Finite Groups, Imam Khomeini International University, Qazvin, Iran, Sept 2022
- Workshop Structure of Group Algebras over Local Rings, Ambleside, Aug 2022
- Méthodes fonctorielles en théorie des groupes, Amiens, Jun 2022
- Workshop Counting Conjectures and Beyond, Isaac Newton Institute, Cambridge, May 2022
- Department of Mathematics & Statistics Colloquium, Maynooth University, April 2022

**2021:**

- Groups in Galway, Galway, Dec. 2021
- Algebra and Symbolic Computations II, Bad Dürkheim, Nov. 2021 [SLIDES]
- Algebra and Number Theory Seminar, UC Santa Cruz, Nov. 2021
- Invited Lecture "Introduction to the Modular Representation Theory of Finite Groups" at the Young Algebraists´Conference 2021, Sept. 2021
- Representation Theory at the Villa Denis 2021, TU Kaiserslautern, July 2021.
- Ringvorlesung, TU Kaiserslautern, July 2021.
- Virtual Algebra Seminar, University of Manchester, May 2021.

**2020:**

- Nikolauskonferenz 2020 (virtual blackboard talk), RWTH Aachen, Dec. 2020.
- Departmental Colloquium of the NIU Department of Mathematical Sciences (virtual slide talk), Northern Illinois University, Nov. 2020.
- Representation Theory at the Villa Denis 2020, TU Kaiserslautern, Sept. 2020. [Photos]
- Departmental Colloquium (virtual) RWTH Aachen, Jul. 2020.
- Representations of Finite Groups: Explicit, Canonical and Functorial, Istanbul, Aug. 2020. (POSTPONED)

**2019:**

- Nikolauskonferenz 2019, RWTH Aachen, Dec. 2019.
- Séminaire de théorie des groupes, Amiens, Sept. 2019.
- NDGK, Martin-Luther-Universität Halle-Wittenberg, Jun. 2019.
- Antalya Algebra Days 2019, Nesin Mathematical Village, Izmir, Turkey, May 2019. [Photo]
- Workshop Representations of Finite Groups, MFO, Oberwolfach, Mar. 2019.

**2018:**

- Darstellungstheorietage 2018, Hannover, Sept. 2018.
- Ringvorlesungen, TU Kaiserslautern, 28. Juni 2018.
- Oberseminar zur Algebra und Algebraischen Kombinatorik, Hannover, Jan. 2018.

**2017:**

- Nikolauskonferenz 2017, RWTH Aachen, Dec. 2017.
- Seminar Groups and Representation Theory, TU Kaiserslautern, Nov. 2017.
- Conference New Perspectives in Representation Theory of Finite Groups, BIRS (Banff), Oct. 2017.
- First annual meeting of the DFG collaborative research center SFB-TRR 195, Aachen, Sept. 2017.
- Conference Algebraic Topology and Representation Theory (ATRT), Lille, Jun. 2017.

**2016:**

- Conference Finite simple groups, their fusion systems and representations, EPFL-CIB, Ecublens, Dec. 2016.
- 5th International Congress on Mathematical Software (ICMS), Berlin, Jul. 11-14 2016.
- Algebra and Geometry Seminar, Bristol, Apr. 2016.
- Oberseminar Darstellungstheorie, Bergische Universität Wuppertal, Jan. 2016.

**2015:**

- "Endo-trivial modules and quotients modulo normal \(p'\)-subgroups", Darstellungstheorietage, Stuttgart, Nov. 2015.
- "Answering a question of Koshitani-Külshammer-Sambale on the Loewy length of blocks" Conference Functorial Methods in Representation Theory, EPFL Ecublens, Sept. 2015.

**2014:**

- "Character theory for endotrivial modules", Nikolauskonferenz, Aachen, Dec. 2014.
- "Character theory for endotrivial modules", Algebra-Seminar Halle-Jena, Universität Halle-Wittemberg, November 2014.
- Séminaire de géométrie, Université de Fribourg, Mar. 2014.
- "Théorie des caractères pour les modules endo-triviaux", Séminaire de théorie des groupes, EPFL, March. 2014.
- "A survey on endo-permutation modules and related classes of modules", Tokyo Japan, March 2014.
- "Reading endo-trivial modules from the Brauer tree", RIMS Symposium
*Research on Finite Groups and their Representations, Vertex Operator Algebras, and Algebraic Combinatorics*, March 2014 - "The position of endo-p-permutation modules and relatives in the AR-quiver", TU Kaiserslautern, Jan. 2014.

**2013:**

- "On simple endo-trivial modules", Nikolauskonferenz, Aachen, Dec. 2013.
- "Reading Endo-trivial modules on the Brauer tree", Birmingham (UK), Oct. 2013.
- "Simple endo-trivial modules for quasi-simple groups", TU Kaiserslautern, Jul. 2013.
- "Le groupe de Dade d'un groupe fini", Séminaire Chevalley, Paris (FR), Jun. 2013.
- "Modules endo-triviaux simples pour les groupes quasi-simples", Amiens (FR), Jun. 2013.
- "Reading simple endo-trivial modules on the Brauer tree", ARTY conference, Friedrich-Alexander-University of Erlangen-Nuremberg, Mai. 2013.
- "Reading simple endo-trivial modules on the Brauer tree", Oberseminar, Jena, Mai. 2013.
- "Balmer's support for relative triangulated categories", Workshop on triangulated categories, EPFL, Feb. 2013.

**2012:**

- "Balmer's support for relative triangulated categories over cyclic p-groups", Nikolauskonferenz 2012, Aachen, Dec. 2012.
- "Endo-permutation modules and the Dade group of a finite group", TU Kaiserslautern, Oct. 2012.
- "Modules via diagrams", 9th Swiss Graduate Colloquium, Neuchatel, Jun. 2012.
- "Le groupe de Dade d'un groupe fini", Séminaire de théorie des groupes, Amiens (FR), Jun. 2012.
- "Coends and the Bousfield-Kan explicit approach", Workshop on homotopy colimits, EPFL, Feb. 2012.

**2011:**

- "The Dade Group of a finite group", Séminaire de théorie des groupes, EPFL, Nov. 2011.
- "Why is there a $k$ summand in the endomorphisms of an endotrivial module ", Séminaire de théorie des groupes, EPFL, Nov. 2011.
- "From relative projectivity to the Dade Group of a finite group", Geometric presentations of finite and infinite groups, Birmingham (UK), Jul. 2011.
- "From relative projectivity to the Dade Group of a finite group", 13th Postgraduate Group Theory Conference, Aberdeen (UK), Jun. 2011.

**2010:**

- "Introduction aux Représentations des Groupes et variété de modules", Master Seminar, EPFL, Dec. 2010.
- "Endo-trivial Modules and Relatives, part II", Group Theory Seminar, EPFL, Sept. 2010.
- "Recovering a Group Scheme from its Representations", Tannakian Categories Workshop, EPFL, Jul. 2010.
- "Endo-trivial Modules and Relatives, part I", Group Theory Seminar, EPFL, Jun. 2010.
- "Endo-trivial Modules and Relatives", 7th Graduate Colloquium, Geneva, Feb. 2010.

**2009-08-07:**

- "Finite/Compact non commutative groups with Haar measures", Group Theory Seminar, May 09.
- "Hopf Algebras according to Milnor and Moore, and more", Group Theory Seminar, Sept. 08.
- "\(p\)-localizations of the infinite complexe projective space and co-H-structure", Topology Seminar, March 07.

### Conferences Organised [+]

**Darstellungstheorietage 2022**

[TU Kaiserslautern, Oct. 28 - 29, 2022] [Organisation: Caroline Lassueur, Gunter Malle] |

**Representation Theory at the Villa Denis**

2024: Sept 27/28 2023: Oct 6/7 2022: Sept 30/Oct 1 2021: Jul 15/16 2020: Sept 17/18 2019: Oct 15 [Organisation: Caroline Lassueur, Gunter Malle. Financial Support: SFB TRR 195, TU Kaiserslautern] |

**Representation Theory in Kaiserslautern**

**Small Workshop: Endo-\(p\)-permutation and trivial source modules in the representation theory of finite groups**

[CIB, Aug. 29 - Sept. 2, 2016] [Financial Support: TU Nachwuchsring, FNS, Schneider Stiftung] [Organisation: Caroline Lassueur [TU Kaiserslautern]] |

**Young Algebraists' Conference 2014**

**Young Algebraists' Conference 2012**

[EPF Lausanne, Ecublens, Switzerland, June 11 to June 15, 2012 | webpage] [Summer School Speakers: R. Kessar (Aberdeen), G. Malle (Kaiserslautern)] [Organisation: Caroline Lassueur, Iulian Ion Simion] |

**February 17 & 18, 2011:**

*7th Swiss Graduate Colloquium*
[EPF Lausanne, Ecublens, Switzerland | Room MA30 | Colloquium webpage] [Organizers: C. Lassueur (EPFL) and D. Moldovan (EPFL)] The colloquium is an activity of the Swiss Doctoral Program in Mathematics |

I also produced the poster of the following:

**June 22 - 25, 2010 :**

*Group Representation Theory and Related Topics*### Doctoral Students [+]

→

**Bernhard Böhmler**[Aug 2018 - Aug 2024 | Thesis | Poster (Nov. 2019)]**Topic**:*Trivial source character tables of small finite groups*### Looking for trivial source modules? [+]

A version zero of a database of trivial source modules can be found here:

Database of

**trivial source modules, preliminary version**