Tobias Barthel

I am a W2 Research Group Leader at the Max Planck Institute of Mathematics in Bonn, interested in homotopy theory and its various interactions with other areas of mathematics. I finished my PhD thesis under the supervision of Mike Hopkins in 2014, then spent the following years as a postdoc in Bonn as well as at the University of Copenhagen, partly supported by an EU Marie Curie Individual Fellowship.


List of publications.

  • Appendices A and B (joint with Krause) to Completing perfect complexes by Henning Krause, with another appendix by Bernhard Keller, accepted in Math. Z. (2020), arXiv link
  • Chromatic homotopy theory is asymptotically algebraic, joint with Tomer Schlank and Nathaniel Stapleton, accepted in Invent. Math. (2019), arXiv link
  • Chromatic structures in stable homotopy theory, joint with Agnès Beaudry, to appear in the Handbook of Homotopy Theory (2019), arXiv link
  • A Whitehead theorem for periodic homotopy groups, joint with Gijs Heuts and Lennart Meier, accepted for publication in Israel. J. Math. (2019), arXiv link
  • Stratifications and duality for homotopical groups, joint with Natalia Castellana, Drew Heard, and Gabriel Valenzuela, accepted for publication in Advances in Mathematics (2019), arXiv link
  • On the Balmer spectrum for compact Lie groups, joint with J.P.C. Greenlees and Markus Hausmann, accepted for publication in Compos. Math. (2019), arXiv link
  • A short introduction to the telescope and chromatic splitting conjectures, accepted for publication in Surveys around Ohkawa's theorem on Bousfield classes, Springer Proc. Math. Stat. (2019), arXiv link
  • Derived completion for comodules, joint with Drew Heard and Gabriel Valenzuela, accepted for publication in Manuscripta Math (2018), arXiv link
  • Gross--Hopkins duals of higher real K-theory spectra, joint with Agnès Beaudry and Vesna Stojanoska, accepted for publication in Trans. Amer. Math. Soc. (2018), arXiv link
  • The Balmer spectrum of the equivariant homotopy category of a finite abelian group, joint with Markus Hausmann, Niko Naumann, Thomas Nikolaus, Justin Noel, and Nathaniel Stapleton, Invent. Math. (2019), arXiv link
  • On the comparison of stable and unstable p-completion, joint with A. K. Bousfield, Proc. Amer. Math. Soc. (2019), arXiv link
  • A simple universal property of Thom ring spectra, joint with Omar Antolin-Camarena, J. Topol. (2019), arXiv link
  • Algebraic chromatic homotopy theory for BP_*BP-comodules, joint with Drew Heard, Proc. Lond. Math. Soc. (2018), arXiv link
  • The chromatic splitting conjecture for Noetherian commutative ring spectra, joint with Drew Heard and Gabriel Valenzuela, Math. Z. (2018), arXiv link
  • Local duality in algebra and topology, joint with Drew Heard and Gabriel Valenzuela, Advances in Mathematics (2018), arXiv link
  • Excellent rings in transchromatic homotopy theory, joint with Nathaniel Stapleton, Homology Homotopy Appl. (2018), arXiv link
  • On localization sequences in the algebraic K-theory of ring spectra, joint with Ben Antieau and David Gepner, J. Eur. Math. Soc. (2018), arXiv link
  • Local duality for structured ring spectra, joint with Drew Heard and Gabriel Valenzuela, J. Pure Appl. Algebra (2018), arXiv link
  • Brown--Peterson cohomology from Morava E-theory, joint with Nathaniel Stapleton and with an appendix by Jeremy Hahn, Compos. Math. (2017), arXiv link
  • Auslander--Reiten sequences, Brown--Comenetz duality, and the K(n)-local generating hypothesis, Algebr. Represent. Theory (2017), arXiv link
  • The character of the total power operation, joint with Nathaniel Stapleton, Geom. Topol. (2017), arXiv link
  • The E_2-term of the K(n)-local E_n-based Adams spectral sequence, joint with Drew Heard, Topology Appl. (2016), arXiv link
  • Chromatic completion, Proc. Amer. Math. Soc. (2016), arXiv link
  • Centralizers in good groups are good, joint with Nathaniel Stapleton, Algebr. Geom. Topol. (2016), arXiv link
  • Completed power operations for Morava E-theory, joint with Martin Frankland, Algebr. Geom. Topol. (2015), arXiv link
  • Six model structures for DG-modules over DGAs, joint with Peter May and Emily Riehl, New York J. Math. (2014), arXiv link
  • On the constructions of functorial factorizations for model categories, joint with Emily Riehl, Algebr. Geom. Topol. (2013), arXiv link

List of preprints.

Here is a video of me speaking about ultrachromatic homotopy theory at Ravenel's 70th birthday conference, Reed College, August 2017

Workshop on Descent and Chromatic homotopy theory

There will be a four-day workshop on descent and chromatic homotopy theory in Strasbourg, 2-5 September 2019, organized by Christian Ausoni, Paul Goerss, Hans-Werner Henn, and myself. For more information, please see the workshop's homepage.

The European Talbot Workshop

Together with Sean Tilson, we started the European Talbot Workshop in 2014. The current organizers are: Bertram Arnold, Luciana Basualdo Bonatto, Jack Davies, and Alice Hedenlund.

The last workshop took place in July 2018. The topic was Free loop spaces in geometry and topology, and the mentors were Nathalie Wahl and Alexandru Oancea. We gratefully acknowledge funding from the SFB 1085 and SPP 1786.


In 2018, I was involved in the organization of two Masterclasses in Copenhagen, together with Jesper Grodal and Markus Hausmann.

In March 2017, Jesper Grodal and I organized a Masterclass on Stratifications and duality in modular representation theory.

My collaborators: Ben Antieau, Omar Antolin-Camarena, Agnès Beaudry, Dan Berwick-Evans, A.K. Bousfield, Natalia Castellana, Martin Frankland, David Gepner, Paul Goerss, Frank Gounelas, J.P.C. Greenlees, Jeremy Hahn, Markus Hausmann, Drew Heard, Gijs Heuts, Bernhard Keller, Achim Krause, Henning Krause, Peter May, Lennart Meier, Niko Naumann, Thomas Nikolaus, Justin Noel, Eric Peterson, Emily Riehl, Tomer Schlank, Nathaniel Stapleton, Vesna Stojanoska, Gabriel Valenzuela.

The above image (Projet de clavier ultrachromatique, 1943) is taken from the book of writings by Wyschnegradsky (Libération du son: écrits 1916-1979, ed. Pascale Criton. Lyon: Symétrie 2013), Ivan Wyschnegradsky Collection, Paul Sacher Stiftung, Basel.