PD Dr. Christine Gaßner

Nach Vereinbarung per E-Mail.

Juli 2023 Mathematisches Kolloquium (Kolloquium des Instituts für Mathematik und Informatik, voraussichtlich am 18. Juli 2023 ab 16 Uhr). 

                 Vortragender: Michael Rathjen (Leeds), Moderation: C. Gaßner.

31. August  – 2. September 2022  Konferenz MCU 2022 (Mitglied des Programmkomitees)

12. – 16. September 2022 C. Gaßner: Second-Order Logic and Russell's Axiom of Choice, DMV Annual Meeting 2022

26. – 28.September 2022  C. Gaßner: Second-Order Henkin Semantics and the Axiom of Choice (Vortrag, Zusammenfassung), CL 2022 (Colloquium Logicum 2022, Konferenz in Konstanz)

26. Juli 2022 Daniel Wessel (Università di Verona, Dipartimento di Informatica): From transfinite to finite proof methods in abstract algebra

• Vortrag am 26.07.2022 ab 11:00 Uhr (per Videokonferenz, Anfragen zum Zugang sind zu richten an gassnerc@uni-greifswald.de)
• Zusammenfassung: Transfinite methods abound in abstract algebra. Barring access to concrete data, however, they tend to undermine whatever computational effort be made along the way. Though certainly dependent on one’s foundational stance, this may appear rather grave within elementary mathematical contexts. Shifting focus to syntax often helps to address such concerns, which strategy is part and parcel of a revised Hilbert programme. The aim of this talk is to discuss and illustrate some of the results, ideas and phenomena. Various prime spectra provide for a range of case studies. In particular, the well-known theorem that every nonconstant coefficient of an invertible polynomial is nilpotent, which via Krull's lemma admits an elegant proof by reduction to the integral case, serves as an acid test. Spotting a straightforward elementary argument, we take a step back to throw a more conceptual glance at the method.

27. Mai 2022 A. Tamminga (Institut für Philosophie):   Two-sided sequent calculi for FDE-like four-valued logics 

• Vortrag am 27.05.2022 ab 12:15 Uhr im SR 5
• Zusammenfassung: We present a method that generates two-sided sequent calculi for four-valued logics like first degree entailment (FDE). (A logic is FDE-like if it has finitely many operators of finite arity, including negation, and if all of its operators are truth-functional over the four truth-values 'none', 'false', 'true', and 'both', where 'true' and 'both' are designated.) First, we show that for every n-ary operator * every truth-table entry f*(x_1,...,x_n) = y can be characterized in terms of a pair of sequent rules. Secondly, we use these sequent rules to build sequent calculi and prove their completeness. With the help of two simplification procedures we then show that the 2x4^n sequent rules that characterize an n-ary operator can be systematically reduced to at most four sequent rules. Thirdly, we use our method to investigate the proof-theoretical consequences of including intuitive truth-functional implications in FDE-like logics. (Joint work with Barteld Kooi.)

23. – 26. Mai 2022 Konferenz CCA 2022

19.05.2022 und 20.05.2022 "Theoretische Informatik" im Rahmen der Hochschulinformationstage

• 19. Mai 2022, 10:00 Uhr   Minivorlesung (Video): "Die Erkennbarkeit von formalen Sprachen",
• 19. Mai 2022, 14:15 Uhr   Minivorlesung/Übung (Online-Diskussion zum Video "Die Erkennbarkeit von formalen Sprachen" 1/2), ​​​​
• 20. Mai 2022, 10:15 Uhr   Minivorlesung (Online-Diskussion zum Video "Die Erkennbarkeit von formalen Sprachen" 2/2).

25.11.2021  C. Gaßner.  The axiom of choice: Different formulations (Vortrag, Institut für Philosophie in Greifswald)

20. – 24. September 2021 Workshop CCC 2021

26. – 28. Juli 2021 Konferenz CCA 2021

05. – 09. Juli 2021 Konferenz Celebrating 90 Years of Gödel's Incompleteness Theorems

2021: Gaßner, Arno Pauly, Florian Steinberg: Computing Measure as a Primitive Operation in Real Number Computation, LIPICS Vol. 183. ISBN 978-3-95977-175-7. CSL 2021 (siehe auch CSL 2021 YouTube channel, EACSL).

2020: Gaßner: An Introduction to a Model of Abstract Computation, in: Adrian Rezus (ed.), Contemporary Logic and Computing, College Publications, London (2020) [Landscapes in Logic 1], pp. 574–603. ISBN: 1848903405 EAN: 9781848903401 (Inhaltsverzeichnis).  Landscapes in Logic:  Series edited by Ali Sadegh Daghighi, Jamshid Derakhshan, Melvin Fitting, Dov Gabbay, Massoud Pourmahdian, and Adrian Rezus.