Trefftz Workshop 2026

7–9 September 2026 · Vienna, Austria

Welcome slides · Card game

Attendees at the Trefftz Workshop 2026 in Vienna

A Century of Trefftz Methods

Trefftz methods are numerical techniques for solving differential equations using basis functions that satisfy the underlying equations. This tailored approach often leads to higher efficiency compared to traditional methods.

Marking 100 years since Erich Trefftz’s seminal 1926 paper, this workshop will celebrate a century of Trefftz methods and look ahead to the future of Trefftz-inspired research.

The workshop is jointly organized by Christoph Lehrenfeld (University of Göttingen) and Paul Stocker (University of Vienna).

Previous Trefftz workshop was held in 2024 · Oaxaca, Mexico.

Registration is now closed. For any questions, please get in touch.

Invited Speakers

Confirmed participants

  • Tobias Born (University of Ulm)

  • Anna Broms (Imperial College London)

  • Théophile Chaumont-Frelet (Inria Lille)

  • Moritz Gallauner (University of Vienna)

  • Jakub Grabski (Poznan University of Technology)

  • Samantha Glory Guiate Simo (University of Göttingen)

  • Astrid Herremans (KU Leuven)

  • Andréa Lagardère (Airbus)

  • Alexei Lozinski (Laboratoire de Mathématiques de Besançon)

  • Markus Melenk (TU Wien)

  • Armando Maria Monforte (University of Pavia)

  • Emile Parolin (Inria)

  • Chiara Perinati (University of Pavia)

  • Ilaria Perugia (University of Vienna)

  • Joachim Schöberl (TU Wien)

  • Jochewed Schmeck (OvGU)

  • Sébastien Tordeux (EPC INRIA Makutu, INRIA-UPPA-CNRS)

  • Igor Tsukerman (The University of Akron)

  • Tim van Beeck (University of Göttingen)

  • Igor Voulis (University of Göttingen)

  • Andreas Wurzinger (Graz University of Technology)

  • Enrico Zampa (University of Vienna)

  • Umberto Zerbinati (University of Oxford)

Venue

Place
Campus of the University of Vienna
Aula, Room 1.11, Campus map
Address
Spitalgasse 2, 1090 Vienna
Public transport
Tram lines 43, 44, and 5 to Lange Gasse

Conference Dinner

Time
Tuesday, 8 September 2026, at 19:00
Place
Heuriger Feuerwehr Wagner
Address
Grinzinger Straße 53, 1190 Wien
Public transport
Tram line 37 to Hohe Warte or tram line 38 to Grinzing; bus 38A to Armbrustergasse is the closest stop.

Timetable

08:30–08:50 Registration
08:50–09:00 Welcome
09:00–09:45 A personal encounter with Erich TrefftzBruno Després
09:45–10:15 Comparing domain decomposition preconditioners for non-conforming Helmholtz discretizationsEmile Parolin
10:15–11:00 Coffee break
11:00–11:30 A locally compressed method of fundamental solutions for near contacts in 2D Stokes flowAnna Broms
11:30–12:00 The Trefftz method with special purpose Trefftz functions and method of fundamental solutions for solving boundary and initial-boundary value problemsJakub Grabski
12:00–14:00 Lunch break (self-organized)
14:00–14:45 Trefftz methods for problems with singularitiesDaan Huybrechs
14:45–15:15 An efficient Galerkin method for high-frequency scattering problems using microlocal Gabor waveletsThéophile Chaumont-Frelet
15:15–16:00 Coffee break
16:00–16:30 A discontinuous Galerkin method for elliptic-hyperbolic equationsChiara Perinati
Evening Discussion & Pizza
09:00–09:45 Trefftz methods in computational electromagnetismPeter Monk
09:45–10:15 Nonlinear TrefftzIgor Voulis
10:15–11:00 Coffee break
11:00–11:30 Comparison of Time-Domain Formulations in Trefftz Methods for Transient Vibroacoustic ProblemsAndreas Wurzinger
11:30–12:00 Trefftz DG Time stepping schemeSamantha Glory Guiate Simo
12:00–14:00 Lunch break (self-organized)
14:00–14:45 A Trefftz Discontinuous Galerkin method in free space using the NtD mapVirginia Selgas
14:45–15:15 Quasi-conforming quasi-Trefftz elementsIgor Tsukerman
15:15–16:00 Coffee break (group photo at 15:15)
16:00–16:45 From Trefftz to quasi-Trefftz methodsLise-Marie Imbert-Gérard
16:45–17:30 Numerical Quasi-Trefftz Method for Helmholtz problemsHélène Barucq (presented by Sébastien Tordeux)
19:00 Conference dinner
09:00–09:45 Trefftz methods with evanescent plane wavesAndrea Moiola
09:45–10:15 An impossibility result on the approximation of singularitiesAstrid Herremans
10:15–11:00 Coffee break
11:00–11:30 Embedded Trefftz DG Least Squares FEMTim van Beeck
11:30–12:00 Discontinuous Galerkin Trefftz Methods for Model Reduction of Wave PhenomenaTobias Born
12:00–14:00 Lunch break (self-organized)
14:00–14:45 Optimal Local Approximation for Generalised Finite ElementsRobert Scheichl
14:45–15:15 Quasi-Trefftz Discontinuous Galerkin Method for the Convected Helmholtz Equation with Smooth CoefficientsAndréa Lagardère
15:15–16:00 Coffee break
16:00–16:30 Trefftz Discontinuous Galerkin Approximation of the T-Matrix for Scattering by Periodic Layered StructuresArmando Maria Monforte
16:30–17:00 Alice, can you hear the liquid crystal drum?Umberto Zerbinati
17:00–17:15 Closing and farewell

Acknowledgements

We gratefully acknowledge the support of our sponsors: the Austrian Science Fund (FWF) Grant ESP4389824 and the University of Göttingen.

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as well as the hospitality of the University of Vienna. University of Vienna Logo