Starting from August 2026 I will be a postdoctoral fellow at the Institute of Computer Science of the Czech Academy of Sciences in Prague, funded by a SNSF Postdoc.Mobility grant.

I am broadly interested in logic and general algebra with a focus on algebraic logic and ordered algebraic structures, but I am also interested in other approaches to logic such as proof theory and relational semantics.

I obtained my PhD degree in Mathematics from the University of Bern in June 2026 under the supervision of George Metcalfe.

1. Logics Containing wK4: Selection à la Fine (with N. C. Vooijs). Proc. AiML 2026, EPTCS 447, Open Publishing Association (2026), 674-690.
2. Interpolation and the Exchange Rule (with W. Fussner and G. Metcalfe). The Journal of Symbolic Logic (2026)
3. Axiomatizing small varieties of periodic ℓ-pregroups (with N. Galatos). Journal of Algebra 688 (2026), 755–802.
4. Amalgamation in Semilinear Residuated Lattices (with W. Fussner). Studia Logica 114, 103–144 (2026).
5. Interpolation in Hájek's Basic Logic (with W. Fussner). Annals of Pure and Applied Logic 176(9) (2025).
6. Equational theories of idempotent semifields (with G. Metcalfe). Bulletin of the London Mathematical Society, 57: 771-785. (2025). (arXiv Preprint)
7. Interpolation in Linear Logic and Related Systems (with W. Fussner). ACM Transactions on Computational Logic, 25, 4, Article 20, (2024). (arXiv Preprint)
8. Semilinear idempotent distributive ℓ-monoids. Journal of Pure and Applied Algebra 228(6) (2024).
9. Deciding Equations in the Time Warp Algebra (with S. van Gool, A. Guatto, and G. Metcalfe). Logical Methods in Computer Science 20(1) (2024), 22 pages.
10. From distributive ℓ-monoids to ℓ-groups, and back again (with A. Colacito, N. Galatos, and G. Metcalfe). Journal of Algebra 601 (2022), 129–148.
11. Time Warps, from Algebra to Algorithms (with S. van Gool, A. Guatto, and G. Metcalfe). Proc. RAMICS 2021, LNCS 13027, Springer (2021), 309-324. (arXiv Preprint)

1. The space of preorders on a commutative monoid (with J. Draisma and G. Metcalfe). Submitted. (arXiv Preprint)
2. Interpolation above S4 (with N. C. Vooijs). (arXiv Preprint)
3. Residuated lattices do not have the amalgamation property (with P. Jipsen). Submitted. (arXiv Preprint)
4. Algebraic Proof Theory for Infinitary Action Logic (with W. Fussner and B. Sierra Miranda). (arXiv Preprint)

• Amalgamation in varieties of residuated lattices. PhD Thesis, University of Bern, 2026.

1. Amalgamation in varieties of residuated lattices, Algebra Week 2025, Siena, Italy, 2025 (Invited talk).
2. Axiomatizing small varieties of periodic ℓ-pregroups, LATD 2025, Siena, Italy, 2025.
3. Right-orders on Free Groups, RAMICS 2024, Prague, Czechia, 2024.
4. Three Theorems on Idempotent Semifields, TACL 2024, Barcelona, Spain, 2024.
5. Interpolation in Substructural Logics I: Logics with Exchange, MOSAIC 2023, Vienna, Austria, 2023.
6. Semilinear idempotent distributive l-monoids, TACL 2022, Coimbra, Portugal, 2022.
7. Time Warps, Special Session on Algebraic Logic of the AMS Spring Western Virtual Sectional Meeting, Denver, Colorado, USA, 2022 (Invited talk).
8. Time Warps, from Algebra to Algorithms, RAMICS 2021, Marseille, France, 2021.

• arXiv: https://arxiv.org/a/santschi_s_1.html
• ORCID: https://orcid.org/0009-0003-9364-5149

Address

Universität Bern

Mathematisches Institut (MAI)

Alpeneggstrasse 22

3012 Bern

Schweiz

Email

simon[dot]santschi[at]unibe.ch