Conference and Workshop Talks

  1. A Feferman-style type system for the small Veblen ordinal, Trends in Proof Theory, Hamburg, September 2015.
  2. Unfolding schematic systems – with an emphasis on inductive definitions, Utrecht Workshop on Proof Theory, Utrecht, April 2015. [pdf]
  3. A flexible type system for the small Veblen ordinal, Conference on Mathematical Logic, Oberwolfach, November 2014.
  4. Unfolding schematic systems: a survey. Humboldt Kolleg Proof, Bern, September 2013.
  5. Unfolding schematic formal systems: From non-finitist to feasible arithmetic, Special Session on Proof Theory, Logic Colloquium ’12, Manchester, July 2012. [pdf]
  6. Types and truth in weak applicative theories, Logical Models of Reasoning and Computation, Moscow, February 2012.
  7. Weak theories of operations, truth and types, Conference on Mathematical Logic, Oberwolfach, November 2011. 
  8. Weak theories of truth and explicit mathematics, Axiomatic Theories of Truth, Oxford, September 2011. [pdf]
  9. Unfolding arithmetic - with an emphasis on finitism, Leeds Symposium on Proof Theory and Constructivism, Leeds, July 2009. [pdf]
  10. Primitive recursive selection functions for existential assertions over abstract algebras, Proof Theory: Workshop on Logic, Foundational Research, and Metamathematics, Münster, July 2008. [pdf]
  11. Weak theories of operations and types, Plenary Lecture, Logic Colloquium '08, Bern, July 2008. [pdf]
  12. Kripke-Platek set theory over polynomial time computable arithmetic, Proof, Computation, Complexity '07, Swansea, Wales, April 2007. [pdf]
  13. On the proof theory of type two functionals, Conference on Mathematical Logic, Oberwolfach, April 2005. [pdf]
  14. On bounded applicative theories and computational complexities, Bounded Arithmetic and Complexity Classes BACC 2002, Lisbon, June 2002.
  15. A proof-theoretic characterization of the basic feasible functionals, Conference on Mathematical Logic, Oberwolfach, April 2002.
  16. Type-free applicative systems: a proof-theoretic approach to complexities, Dagstuhl seminar on Proof Theory in Computer Science, Dagstuhl, October 2001. (not delivered because of illness).
  17. Unfolding finitist arithmetic, Logic Colloquium 2000, Paris, July 2000.
  18. Bounded applicative theories, Logic Colloquium 2000, Paris, July 2000.
  19. Theories with self-application and computational complexity, Workshop on Proof and Computation, Munich, November 1999.
  20. Bar induction and omega model reflection, Research Workshop on Proof Theory, Leeds, February 1999.
  21. Reflective closures of formal systems, Reflections Symposium, Stanford, December 1998.
  22. Universes in explicit mathematics and admissible set theory, Workshop on Operations, Sets, and Types, Castiglioncello, October 1998.
  23. Metapredicativity, Plenary lecture, Logic Colloquium ’98, Prague, August 1998.
  24. Abstract computations in type-free applicative systems, Workshop on Proof Theory and Complexity, Aarhus, August 1998.
  25. Metapredicativity, Conference on Mathematical Logic, Oberwolfach, January 1998.
  26. Aspects of metapredicativity, Special Session on Proof Theory, Logic Colloquium ’97, Leeds, July 1997.
  27. The unfolding of non-finitist arithmetic, Workshop on Proof Theory and Ordinal Analyses, Münster, May 1997.
  28. The non-constructive µ operator in explicit mathematics: a survey, Workshop on Applicative Theories and Explicit Mathematics, Berne, June 1996.
  29. Systems of explicit mathematics with primitive recursive operations plus non-constructive µ operator, 10th International Congress of Logic, Methodology and Philosophy of Science, Florence, August 1995.
  30. Polynomial time operations in explicit mathematics, Special Session on Proof Theory, Logic Colloquium ’95, Haifa, August 1995.
  31. Polynomial time operations in applicative theories, Conference on Mathematical Logic, Oberwolfach, April 1995.
  32. Induction in applicative theories, EC Workshop on Proof Theory and Computation, Leeds, September 1994.
  33. Partiality versus totality in applicative theories, International conference on Proof Theory, Provability Logic, and Computation PPC ’94, Berne, March 1994.
  34. Applicative theories and term models, Workshop on Applicative Theories, Berne, March 1994.

Colloquia and Seminar Talks

  1. Finitely stratified inductive definitions, Stanford Logic Seminar, Stanford, October, 2013. [pdf]
  2. Weak theories of explicit mathematics and positive truth, Stanford Logic Seminar, Standford, July, 2012.
  3. Das P-NP-Problem und die Grenzen der praktischen Berechenbarkeit, Fachschaftstagung Informatik, Mathematik und Physik, Gymnasium Muristalden, Berne, November 2010. [pdf]
  4. The unfolding of non-finitist and finitist arithmetic, Philosophy of Mathematics Seminar, University of Oxford, May 2010.
  5. Two unfoldings of finitist arithmetic, Proof, Complexity and Verification Seminar, University of Swansea, Wales, April 2010. [pdf]
  6. Unfolding arithmetic, Logic Seminar, University of Florence, December 2008.
  7. Einige Ideen und Probleme der theoretischen Informatik, Kolloquium Informatik und Unterricht, Berne, January 2008. [pdf]
  8. Unfolding schematic formal systems, Swiss-South African Joint Seminar, Berne, January 2007. [pdf]
  9. Logik im interdisziplinären Spannungsfeld zwischen Informatik, Mathematik und Philosophie, Fachschaftstagung Mathematik, Gymnasium Köniz, November 2004. [pdf]
  10. Logik in Informatik und Mathematik, Forum Mathematik und Unterricht,  Berne, May 2004.
  11. Das P-NP-Problem und die Grenzen der praktischen Berechenbarkeit, Habilitations-Kolloquium, Berne, June 2001.
  12. Untyped applicative theories and computational complexity, Mittag-Leffler seminar, Institute Mittag-Leffler, Stockholm, March 2001.
  13. Applicative theories and classes of computational complexity, Logic Seminar, University of Florence, May 2000.
  14. Applikative Theorien und Komplexität, Computer Science Colloquium, University of Tübingen, January 2000.
  15. The implicitness program, Philosophical Colloquium, University of Bonn, November 1999.
  16. Logik in Informatik, Mathematik und Philosophie, Theodor Kocher award lecture, University of Berne, January 1999. [pdf]
  17. Recent results in metapredicative proof theory, Stanford Logic Seminar, March-April 1998.
  18. Abstrakte Berechnungen in expliziter Mathematik, Seminar Theoretische Informatik und Logik, Schloss Münchenwiler, April 1997.
  19. Zur Beweistheorie von applikativen Theorien, PhD defense, Berne, June 1996.
  20. Polynomial time operations in applicative theories, Logic Colloquium, SRI International, Menlo Park, December 1995.
  21. Some new proof-theoretic results about explicit mathematics with non-constructive µ operator, Stanford Logic Seminar, October 1995.
  22. Beweise als Progamme, Colloquium Philosophical Society Berne, June 1994.
  23. Numerous talks in the seminar Logik und Informatik (Berne-Zurich), the colloquium Deduktive Aspekte von Beweistheorie und Informatik (Berne-Munich), and the Münchenwiler seminar Logic and Information (Berne-Fribourg-Neuchâtel).
A list of publications and talks in pdf-format can be downloaded here.