Research

Publications

2024

Multiplicity-free Representations of Algebraic Groups

M. W. Liebeck; G. M. Seitz; D. M. Testerman 

Memoirs Of The American Mathematical Society. 2024-02-01. Vol. 294, num. 1466, p. 1-282. DOI : 10.1090/memo/1466.

2023

On minimal epimorphic subgroups in simple algebraic groups of rank 2

I. I. Simion; D. M. Testerman 

Journal Of Pure And Applied Algebra. 2023-12-01. Vol. 228, num. 6, p. 107572. DOI : 10.1016/j.jpaa.2023.107572.

Almost Cyclic Regular Semisimple Elements In Irreducible Representations Of Simple Algebraic Groups

D. M. Testerman; A. E. Zalesski 

Transformation Groups. 2023-02-20. DOI : 10.1007/s00031-023-09793-5.

Cohomology in singular blocks of parabolic category O

J. Gruber 

Glasgow Mathematical Journal. 2023-05-15.  p. 1-14. DOI : 10.1017/S0017089523000113.

Duality and bicrystals on infinite binary matrices

T. Gerber; C. Lecouvey 

Annales de l’Institut Henri Poincaré D: Combinatorics, Physics and their Interactions. 2023-05-13. DOI : 10.4171/aihpd/165.

2022

Multiplicity-free representations of algebraic groups II

M. W. Liebeck; G. M. Seitz; D. M. Testerman 

Journal Of Algebra. 2022-10-01. Vol. 607, p. 531-606. DOI : 10.1016/j.jalgebra.2021.07.003.

On minimal tilting complexes in highest weight categories

J. Gruber 

Algebras and Representation Theory. 2022. Vol. 32, p. 1-31. DOI : 10.1007/s10468-022-10188-5.

Atomic length in Weyl groups

N. Chapelier-Laget; T. Gerber 

2022. DOI : 10.48550/arxiv.2211.12359.

Generalised Howe duality and injectivity of induction: the symplectic case

T. Gerber; J. Guilhot; C. Lecouvey 

Combinatorial Theory. 2022-06-30. Vol. 2, num. 2. DOI : 10.5070/C62257878.

Eigenvalue multiplicities of group elements in irreducible representations of simple linear algebraic groups

A-M. Retegan / D. Testerman (Dir.)  

Lausanne, EPFL, 2022. 

Generic direct summands of tensor products for simple algebraic groups and quantum groups at roots of unity

J. Gruber / D. Testerman (Dir.)  

Lausanne, EPFL, 2022. 

Coxeter Combinatorics For Sum Formulas In The Representation Theory Of Algebraic Groups

J. Gruber 

Representation Theory. 2022-03-02. Vol. 26, p. 68-93. DOI : 10.1090/ert/599.

2021

Spectra of non-regular elements in irreducible representations of simple algebraic groups

D. Testerman; A. Zalesski 

North-Western European Journal of Mathematics. 2021-12-02. Vol. 7, p. 185-212.

On complete reducibility of tensor products of simple modules over simple algebraic groups

J. Gruber 

Transactions of the American Mathematical Society, Series. 2021. Vol. B8, num. 8, p. 249-276. DOI : 10.1090/btran/58.

Spherical birational sheets in reductive groups

F. Ambrosio; M. Costantini 

Journal Of Algebra. 2021-12-01. Vol. 587, p. 488-521. DOI : 10.1016/j.jalgebra.2021.07.036.

2020

Generalized Mullineux Involution And Perverse Equivalences

T. Gerber; N. Jacon; E. Norton 

Pacific Journal Of Mathematics. 2020-06-01. Vol. 306, num. 2, p. 487-517. DOI : 10.2140/pjm.2020.306.487.

A positive combinatorial formula for symplectic Kostka-Foulkes polynomials I: Rows

M. Dolega; T. Gerber; J. Torres 

Journal Of Algebra. 2020-10-15. Vol. 560, p. 1253-1296. DOI : 10.1016/j.jalgebra.2020.05.030.

2019

$A_1$-type subgroups containing regular unipotent elements

T. C. Burness; D. Testerman 

Forum of Mathematics, Sigma. 2019-04-24. Vol. 7, p. E12. DOI : 10.1017/fms.2019.12.

Irreducible Subgroups of Simple Algebraic Groups – A Survey

T. C. Burness; D. Testerman 

Groups St Andrews 2017 in Birmingham; Cambridge: Cambridge University Press, 2019-04-01. p. 230-260.

Minimal Polynomials Of Unipotent Elements Of Non-Prime Order In Irreducible Representations Of The Exceptional Algebraic Groups In Some Good Characteristics

T. S. Busel; I. D. Suprunenko; D. Testerman 

Doklady Natsionalnoi Akademii Nauk Belarusi. 2019-01-01. Vol. 63, num. 5, p. 519-525. DOI : 10.29235/1561-8323-2019-63-5-519-525.

Jordan blocks of unipotent elements in some irreducible representations of classical groups in good characteristic

M. T. Korhonen 

Proceedings of the American Mathematical Society. 2019-06-19. Vol. 147, p. 4205-4219. DOI : 10.1090/proc/14570.

A new family of irreducible subgroups of the orthogonal algebraic groups

M. Cavallin; D. Testerman 

Transactions of the American Mathematical Society, Series B. 2019. Vol. 6, p. 45-79. DOI : 10.1090/btran/28.

Maximal subgroups acting with two composition factors on irreducible representations of exceptional algebraic groups

N. Scheinmann / D. Testerman (Dir.)  

Lausanne, EPFL, 2019. 

2018

Local Representation Theory and Simple Groups

R. Kessar; G. Malle; D. Testerman 

Zurich: European Mathematical Society, 2018-04-01.

Irreducible components of exotic Springer fibres

V. Nandakumar; D. Rosso; N. Saunders 

Journal of the London Mathematical Society. 2018-12-01. Vol. 98, num. 3, p. 609-637. DOI : 10.1112/jlms.12152.

Structure of certain Weyl modules for the Spin groups

M. Cavallin 

Journal of Algebra. 2018-07-01. Vol. 505, p. 420-455. DOI : 10.1016/j.jalgebra.2018.03.007.

Unipotent elements forcing irreducibility in linear algebraic groups

M. Korhonen 

JOURNAL OF GROUP THEORY. 2018. Vol. 21, num. 3, p. 365-396. DOI : 10.1515/jgth-2018-0003.

Reductive overgroups of distinguished unipotent elements in simple algebraic groups

M. T. Korhonen / D. Testerman (Dir.)  

Lausanne, EPFL, 2018. 

Irreducible representations of simple algebraic groups in which a unipotent element is represented by a matrix with a single non-trivial Jordan block

D. M. Testerman; A. E. Zalesski 

Journal Of Group Theory. 2018. Vol. 21, num. 1, p. 1-20. DOI : 10.1515/jgth-2017-0019.

2017

Restriction of irreducible modules for Spin2+1(K) to Spin2(K)

M. Cavallin 

Journal of Algebra. 2017-04-01. Vol. 482, p. 159-203. DOI : 10.1016/j.jalgebra.2017.03.019.

An algorithm for computing weight multiplicities in irreducible modules for complex semisimple Lie algebras

M. Cavallin 

Journal of Algebra. 2017-02-01. Vol. 471, p. 492-510. DOI : 10.1016/j.jalgebra.2016.08.044.

Invariant forms on irreducible modules of simple algebraic groups

M. Korhonen 

Journal Of Algebra. 2017. Vol. 480, p. 385-422. DOI : 10.1016/j.jalgebra.2017.02.031.

On irreducible subgroups of simple algebraic groups

T. C. Burness; C. Marion; D. M. Testerman 

Mathematische Annalen. 2017. Vol. 367, num. 3-4, p. 1259-1309. DOI : 10.1007/s00208-016-1432-z.

2016

Central Subalgebras Of The Centralizer Of A Nilpotent Element

G. J. Mcninch; D. M. Testerman 

Proceedings Of The American Mathematical Society. 2016. Vol. 144, num. 6, p. 2383-2397. DOI : 10.1090/proc/12942.

2015

Witt overgroups for unipotent elements in exceptional algebraic groups of bad characteristic

I. I. Simion 

Mathematica. 2015. Vol. 57, num. 80, p. 104-116.

Double centralizers of unipotent elements in simple algebraic groups of type $E_7$ and $E_8$

I. I. Simion 

Journal of Pure and Applied Algebra. 2015-04-04. Vol. 219, num. 4, p. 930-977. DOI : 10.1016/j.jpaa.2014.05.027.

Irreducible Geometric Subgroups of Classical Algebraic Groups

T. C. Burness; S. Ghandour; D. Testerman 

Providence: American Mathematical Society, 2015.

Distinguished unipotent elements and multiplicity-free subgroups of simple algebraic groups

M. W. Liebeck; G. M. Seitz; D. Testerman 

Pacific Journal of Mathematics. 2015. Vol. 279, num. 1-2, p. 357–382. DOI : 10.2140/pjm.2015.279.357.

Irreducible almost simple subgroups of classical algebraic groups

T. C. Burness; S. Ghandour; C. Marion; D. Testerman 

Providence: American Mathematical Society, 2015.

Subgroups Of Simple Algebraic Groups Containing Regular Tori, And Irreducible Representations With Multiplicity 1 Non-Zero Weights

D. Testerman; A. E. Zalesski 

Transformation Groups. 2015. Vol. 20, num. 3, p. 831-861. DOI : 10.1007/s00031-015-9321-1.

Restricting representations of classical algebraic groups to maximal subgroups

M. Cavallin / D. Testerman (Dir.)  

Lausanne, EPFL, 2015. 

2014

Unipotent Overgroups in Simple Algebraic Groups

I. I. Simion; D. Testerman 

Groups of Exceptional Type, Coxeter Groups and Related Geometries; New Dehli: Springer, 2014-04-03. p. 147-158.

2013

Double centralizers of unipotent elements in simple algebraic groups of type G2, F4 and E6

I. I. Simion 

Journal of Algebra. 2013. Vol. 382, p. 335-367. DOI : 10.1016/j.jalgebra.2013.03.003.

Irreducibility In Algebraic Groups And Regular Unipotent Elements

D. Testerman; A. Zalesski 

Proceedings Of The American Mathematical Society. 2013. Vol. 141, num. 1, p. 13-28. DOI : 10.1090/S0002-9939-2012-11898-2.

On the irreducibility of symmetrizations of cross-characteristic representations of finite classical groups

K. Magaard; G. Roehrle; D. Testerman 

Journal of Pure and Applied Algebra. 2013. Vol. 217, num. 8, p. 1427-1446. DOI : 10.1016/j.jpaa.2012.11.004.

Centers of Centralizers of Unipotent Elements in Exceptional Algebraic Groups

I. I. Simion / D. Testerman (Dir.)  

Lausanne, EPFL, 2013. 

2011

Linear Algebraic Groups and Finite Groups of Lie Type

G. Malle; D. Testerman 

Cambridge: Cambridge University Press, 2011.

Centres of centralizers of unipotent elements in simple algebraic groups

D. Testerman; R. Lawther 

Memoirs of the American Mathematical Society. 2011. Vol. 210, num. 988, p. 1-185. DOI : 10.1090/S0065-9266-10-00594-6.

2010

Irreducible disconnected subgroups of exceptional algebraic groups

S. Ghandour 

Journal of Algebra. 2010-05-15. Vol. 323, p. 2671-2709. DOI : 10.1016/j.jalgebra.2010.02.018.

Tensor Products of Weil Modules

A. Monnard 

2010.

2009

Nilpotent subalgebras of semisimple Lie algebras

P. Levy; G. McNinch; D. Testerman 

Comptes Rendus Mathematique. 2009. Vol. 347, p. 477-482. DOI : 10.1016/j.crma.2009.03.015.

Nilpotent centralizers and Springer isomorphisms

G. J. McNinch; D. Testerman 

Journal of Pure and Applied Algebra. 2009. Vol. 213, num. 7, p. 1346-1363. DOI : 10.1016/j.jpaa.2008.12.007.

2008

Irreducibility of disconnected subgroups of exceptional algebraic groups

S. N. Ghandour / D. M. Testerman (Dir.)  

Lausanne, EPFL, 2008. 

2007

Double centralizers of unipotent elements

D. Testerman; R. Lawther 

2007

Group representation theory. Based on the research semester “Group representation theory”, Lausanne, Switzerland, January – June, 2005

M. Geck; D. Testerman; J. Thévenaz 

Lausanne; Boca Raton: EPFL Press; CRC Press, 2007.

Completely reducible $\text{SL}(2)$-homomorphisms

G. J. McNinch; D. Testerman 

Transactions of the American Mathematical Society. 2007. Vol. 359, num. 9, p. 4489-4510. DOI : 10.1090/S0002-9947-07-04289-4.

2004

Irreducible subgroups of algebraic groups

M. W. Liebeck; D. Testerman 

Quarterly Journal of Mathematics. 2004. Vol. 55, num. 1, p. 47-55. DOI : 10.1093/qmath/hag042.

2000

Subgroups of type $A_1$ containing a fixed unipotent element in an algebraic group

R. Proud; J. Saxl; D. Testerman 

Journal of Algebra. 2000. Vol. 231, num. 1, p. 53-66. DOI : 10.1006/jabr.2000.8353.

1999

$A_1$ subgroups of exceptional algebraic groups

R. Lawther; D. Testerman 

1999.

1997

Subgroups of type $A_1$ containing semiregular unipotent elements

G. M. Seitz; D. Testerman 

Journal of Algebra. 1997. Vol. 196, num. 2, p. 595-619. DOI : 10.1006/jabr.1997.7099.

1996

Simple subgroups of large rank in groups of Lie type

M. W. Liebeck; J. Saxl; D. Testerman 

Proceedings of the London Mathematical Society, Third Series***. 1996. Vol. 72, num. 2, p. 425-457. DOI : 10.1112/plms/s3-72.2.425.

1995

$A_1$-type overgroups of elements of order $p$ in semisimple algebraic groups and the associated finite groups

D. Testerman 

Journal of Algebra. 1995. Vol. 177, num. 1, p. 34-76. DOI : 10.1006/jabr.1995.1285.

1992

The construction of the maximal $A_1$’s in the exceptional algebraic groups

D. Testerman 

Proceedings of the American Mathematical Society. 1992. Vol. 116, num. 3, p. 635-644. DOI : 10.1090/S0002-9939-1992-1100666-2.

Overgroups of unipotent elements in simple algebraic groups

D. Testerman 

1992. L.M.S. Durham symposium, Durham, UK, July 5-15, 1990. p. 333-339. DOI : 10.1017/CBO9780511629259.029.

1990

Extending morphisms from finite to algebraic groups

G. M. Seitz; D. Testerman 

Journal of Algebra. 1990. Vol. 131, num. 2, p. 559-574. DOI : 10.1016/0021-8693(90)90195-T.

1989

A construction of certain maximal subgroups of the algebraic groups $E\sub{6}$ and $F\sub{4}$

D. Testerman 

Journal of Algebra. 1989. Vol. 122, num. 2, p. 299-322. DOI : 10.1016/0021-8693(89)90218-4.

A note on composition factors of Weyl modules

D. Testerman 

Communications in Algebra. 1989. Vol. 17, num. 4, p. 1003-1016. DOI : 10.1080/00927878908823771.

1988

Irreducible subgroups of exceptional algebraic groups

D. Testerman 

1988.