## Conference and Workshop Talks

- A Feferman-style type system for the small Veblen ordinal, Trends in Proof Theory, Hamburg, September 2015.
- Unfolding schematic systems – with an emphasis on inductive definitions, Utrecht Workshop on Proof Theory, Utrecht, April 2015. [pdf]

- A flexible type system for the small Veblen ordinal, Conference on Mathematical Logic,
Oberwolfach, November 2014.

- Unfolding schematic systems: a survey. Humboldt Kolleg Proof, Bern, September 2013.

- Unfolding schematic formal systems: From non-finitist to feasible arithmetic, Special Session on Proof Theory, Logic Colloquium ’12, Manchester, July 2012. [pdf]

- Types and truth in weak applicative theories, Logical Models of Reasoning and Computation, Moscow, February 2012.

- Weak theories of operations, truth and types, Conference on Mathematical Logic, Oberwolfach, November 2011.
- Weak theories of truth and explicit mathematics, Axiomatic Theories of Truth, Oxford, September 2011. [pdf]
- Unfolding arithmetic - with an emphasis on finitism, Leeds Symposium on Proof Theory and Constructivism, Leeds, July 2009. [pdf]
- Primitive recursive selection functions for existential assertions over abstract algebras, Proof Theory: Workshop on Logic, Foundational Research, and Metamathematics, Münster, July 2008. [pdf]
- Weak theories of operations and types, Plenary Lecture, Logic Colloquium '08, Bern, July 2008. [pdf]
- Kripke-Platek set theory over
polynomial time computable arithmetic, Proof, Computation, Complexity '07,
Swansea, Wales, April 2007. [pdf]

- On the proof theory of type two functionals, Conference on Mathematical Logic, Oberwolfach, April 2005. [pdf]
- On bounded applicative theories and computational complexities, Bounded Arithmetic and Complexity Classes BACC 2002, Lisbon, June 2002.
- A proof-theoretic characterization of the basic feasible functionals, Conference on Mathematical Logic, Oberwolfach, April 2002.
- 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).
- Unfolding finitist arithmetic, Logic Colloquium 2000, Paris, July 2000.
- Bounded applicative theories, Logic Colloquium 2000, Paris, July 2000.
- Theories with self-application and computational complexity, Workshop on Proof and Computation, Munich, November 1999.
- Bar induction and omega model reflection, Research Workshop on Proof Theory, Leeds, February 1999.
- Reflective closures of formal systems, Reflections Symposium, Stanford, December 1998.
- Universes in explicit mathematics and admissible set theory, Workshop on Operations, Sets, and Types, Castiglioncello, October 1998.
- Metapredicativity, Plenary lecture, Logic Colloquium ’98, Prague, August 1998.
- Abstract computations in type-free applicative systems, Workshop on Proof Theory and Complexity, Aarhus, August 1998.
- Metapredicativity, Conference on Mathematical Logic, Oberwolfach, January 1998.
- Aspects of metapredicativity, Special Session on Proof Theory, Logic Colloquium ’97, Leeds, July 1997.
- The unfolding of non-finitist arithmetic, Workshop on Proof Theory and Ordinal Analyses, Münster, May 1997.
- The non-constructive µ operator in explicit mathematics: a survey, Workshop on Applicative Theories and Explicit Mathematics, Berne, June 1996.
- 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.
- Polynomial time operations in explicit mathematics, Special Session on Proof Theory, Logic Colloquium ’95, Haifa, August 1995.
- Polynomial time operations in applicative theories, Conference on Mathematical Logic, Oberwolfach, April 1995.
- Induction in applicative theories, EC Workshop on Proof Theory and Computation, Leeds, September 1994.
- Partiality versus totality in applicative theories, International conference on Proof Theory, Provability Logic, and Computation PPC ’94, Berne, March 1994.
- Applicative theories and term models, Workshop on Applicative Theories, Berne, March 1994.

## Colloquia and Seminar Talks

- Finitely stratified inductive definitions, Stanford Logic Seminar, Stanford, October, 2013. [pdf]

- Weak theories of explicit mathematics and positive truth, Stanford Logic Seminar, Standford, July, 2012.

- Das P-NP-Problem und die Grenzen der praktischen Berechenbarkeit,
Fachschaftstagung Informatik,
Mathematik und Physik, Gymnasium Muristalden, Berne, November
2010. [pdf]

- The unfolding of non-finitist and finitist arithmetic, Philosophy of Mathematics Seminar, University of Oxford, May 2010.
- Two unfoldings of finitist arithmetic, Proof, Complexity and Verification Seminar, University of Swansea, Wales, April 2010. [pdf]
- Unfolding arithmetic, Logic Seminar, University of Florence, December 2008.
- Einige Ideen und Probleme der theoretischen Informatik, Kolloquium Informatik und Unterricht, Berne, January 2008. [pdf]
- Unfolding schematic formal systems, Swiss-South African Joint Seminar, Berne, January 2007. [pdf]
- Logik im interdisziplinären Spannungsfeld zwischen Informatik, Mathematik und Philosophie, Fachschaftstagung Mathematik, Gymnasium Köniz, November 2004. [pdf]
- Logik in Informatik und Mathematik, Forum Mathematik und Unterricht, Berne, May 2004.
- Das P-NP-Problem und die Grenzen der praktischen Berechenbarkeit, Habilitations-Kolloquium, Berne, June 2001.
- Untyped applicative theories and computational complexity, Mittag-Leffler seminar, Institute Mittag-Leffler, Stockholm, March 2001.
- Applicative theories and classes of computational complexity, Logic Seminar, University of Florence, May 2000.
- Applikative Theorien und Komplexität, Computer Science Colloquium, University of Tübingen, January 2000.
- The implicitness program, Philosophical Colloquium, University of Bonn, November 1999.
- Logik in Informatik, Mathematik und Philosophie, Theodor Kocher award lecture, University of Berne, January 1999. [pdf]
- Recent results in metapredicative proof theory, Stanford Logic Seminar, March-April 1998.
- Abstrakte Berechnungen in expliziter Mathematik, Seminar Theoretische Informatik und Logik, Schloss Münchenwiler, April 1997.
- Zur Beweistheorie von applikativen Theorien, PhD defense, Berne, June 1996.
- Polynomial time operations in applicative theories, Logic Colloquium, SRI International, Menlo Park, December 1995.
- Some new proof-theoretic results about explicit mathematics with non-constructive µ operator, Stanford Logic Seminar, October 1995.
- Beweise als Progamme, Colloquium Philosophical Society Berne, June 1994.
- 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).