Original post on fediscience.org

8th Workshop on Intuitionistic Modal Logic and Applications (IMLA)
24–25 July 2026, Lisbon, Portugal
Affiliated with the Federated Logic Conference (FLoC 26)
https://sonia-marin.github.io/imla26/

Constructive and intuitionistic modal logics, and their connections with type theory and […]

Argument: Classical Modal Logic Applies to Beings, but Not to Being

Classical modal logic presupposes a space of possibilities.
This space is modelled by possible worlds, relative to which modal operators are evaluated.

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#Philosophy #Philsky #ModalLogic #Ontology

A fresh take on modal expressions like “necessary” or “possible” — blending logic, pragmatics & ontology to resolve long-standing semantic puzzles. 🔍✨
Essential reading for anyone into philosophy of language or modal logic.
brill.com/display/ti...
#ModalLogic #Pragmatics

People working on non-deterministic semantics flaunt that they can do modal logic without possible worlds. But do they have a theory modality?

Yesterday in Ghent I argued that they do. Thanks for the invite, I met many people who I cite, which now I can call colleagues.
#metaphysics #modallogic

Complexity of Separating Fixpoint Formulae in Modal Logic

The separability problem for modal fixpoint formulas is PSpace‑complete on words and ExpTime‑complete on unrestricted and binary models, with TwoExpTime‑complete hardness when outdegree ≥3. getnews.me/complexity-of-separating... #modallogic #complexity

6/10: Ott proposes a fourfold systematics: logical (modal basics), empirical (factual alternatives), epistemic (limited knowledge), and technical (simulations), applied to physics, philosophy, and society. #ModalLogic #Sociology

Original post on fediscience.org

In this week's #blog I write briefly about a 2001 paper on designing lambda calculi for intuitionistic modal logic. blogs.fediscience.org/the-updated-scholar/2025... #logic #modalLogic #proofTheory […]

Ever debated what *must* be true for an argument to hold? Necessity in logic (Q2301186) sparked medieval scholastic clashes—Aquinas vs. skeptics—and still shapes modern AI reasoning! #ModalLogic #ScholasticDebate

Semantical Analysis of Intuitionistic Modal Logics between CK and IK The intuitionistic modal logics considered between Constructive K (CK) and Intuitionistic K (IK) differ in their treatment of the possibility (diamond) connective. It was recently rediscovered that some logics between CK and IK also disagree on their diamond-free fragments, with only some remaining conservative over the standard axiomatisation of intuitionistic modal logic with necessity (box) alone. We show that relational Kripke semantics for CK can be extended with frame conditions for all axioms in the standard axiomatisation of IK, as well as other axioms previously studied. This allows us to answer open questions about the (non-)conservativity of such logics over intuitionistic modal logic without diamond. Our results are formalised using the Coq Proof Assistant.

My paper 'Semantical Analysis of Intuitionistic Modal Logics between CK and IK', with Jim de Groot and Ian Shillito, is now in its final edited preprint form: https://arxiv.org/abs/2408.00262 . I will travelling to #LICS #LICS2025 to present it in Singapore in late June. #logic #modalLogic

A view across a broad canal in central Amsterdam, with canal boats moored to the right, and a series of terrace buildings on view behind them.

A smaller Amsterdam canal viewed from a brick bridge overpass.

I’m in Amsterdam, about to give a talk about proof theory for modal predicate logic at the ILLC, the home base of the modal industrial complex. I have no idea how this is going to go over, but it should be a fun ride, however it turns out […]

[Original post on hcommons.social]

A screen containing a series of clauses in the proof theory of quantified modal logic, above a mechanical keyboard with dark blue and light blue keycaps.

It’s a cloudy and cold Tuesday, and I’m inside writing about refinement.

At least I *think* I understand what I’m doing a bit better than Mark S and his team of macrodata refiners do.

(That’s an inappropriate #Severance, #prooftheory #ModalLogic and […]

[Original post on hcommons.social]

What is the significance of the K-axiom in modal logic S5? In normal modal logic S5, the K axiom says $\square (p \rightarrow q) \rightarrow (\square p \rightarrow \square q)$. First of all, is this an abuse...

An explanation of what axioms and mathematical proofs really are. With a reference to my tool that helps exploring some of them.

#Logic #Axioms #Mathematics #ProofTheory #HilbertSystems #ModalLogic #Research #Software

Sharing an early poem of mine published in Soundings East!

#poetry #experimentalpoetry #avantgarde #micropoetry #modallogic #logic