arXiv subjects

Miguel Martins

Publications and source records attributed to Miguel Martins.

3 recordsLinked to original sources

arXiv2026

There are only countably many locally tabular bi-intermediate logics of co-trees

A bi-Heyting algebra validates the Gödel-Dummett axiom $(p \to q) \lor (q \to p)$ iff the poset of its prime filters is a disjoint union of co-trees. Bi-Heyting algebras of this kind are called bi-Gödel algebras and form a variety $\operatorname{\mathsf{bi-GA}}$ that algebraizes the extension $\operatorname{\mathsf{bi-GD}}$ of bi-intuitionistic logic axiomatized by the Gödel-Dummett axiom. In this paper we show that there are only countably many locally tabular bi-intermediate logics of co-trees, all of which are finitely axiomatizable. The theory of canonical formulas of bi-Gödel algebras has shown that $\operatorname{\mathsf{bi-GA}}$ has continuum many subvarieties, among which the locally finite ones coincide with the subvarieties of the $\mathsf{V}_n \coloneqq \{\mathbf{A} \in \operatorname{\mathsf{bi-GA}} \colon \mathbf{A} \models β(\mathfrak{C}_n)\}$ (where $β(\mathfrak{C}_n)$ is the subframe formula of the $n$-comb). We identify the multiset projectivity relation (a binary relation that, when defined on the set of finite multisets of a better partial order, is necessarily a better partial order) and use it to prove that every $\mathsf{V}_n$ is a Specht variety, hence has only countably many subvarieties, all of which are finitely axiomatizable. By the algebraizability of $\operatorname{\mathsf{bi-GD}}$, the main result follows. We also provide an informative depiction of the lattice of varieties of bi-Gödel algebras.

math.LO↗

arXiv2024

Local Tabularity is Decidable for Bi-Intermediate Logics of Trees and of Co-Trees

A bi-Heyting algebra validates the Gödel-Dummett axiom $(p\to q)\vee (q\to p)$ iff the poset of its prime filters is a disjoint union of co-trees (i.e., order duals of trees). Bi-Heyting algebras of this kind are called bi-Gödel algebras and form a variety that algebraizes the extension $\operatorname{\mathsf{bi-GD}}$ of bi-intuitionistic logic axiomatized by the Gödel-Dummett axiom. In this paper we establish the decidability of the problem of determining if a finitely axiomatizable extension of $\operatorname{\mathsf{bi-GD}}$ is locally tabular. Notably, if $L$ is an extension of $\operatorname{\mathsf{bi-GD}}$, then $L$ is locally tabular iff $L$ is not contained in $Log(FC)$, the logic of a particular family of finite co-trees, called the finite combs. We prove that $Log(FC)$ is finitely axiomatizable. Since this logic also has the finite model property, it is therefore decidable. Thus, the above characterization of local tabularity ensures the decidability of the aforementioned problem.

math.LO↗

arXiv2019

Probing the high energy spectrum of neutral pions in ultra-high energy proton-Air interactions

The interaction of ultra-high energy cosmic rays with the atmosphere nuclei has long been seen as a unique opportunity to study hadronic interactions above energies attainable by accelerators. However, so far the multiparticle production properties of the first interaction have been difficult to assess as they are masked by the many interactions that outline the shower development. In this work, we demonstrate, that relevant properties of the ultra-high energy first interaction can be accessed through the analysis of the shower-to-shower distribution of muons arriving at the ground. In particular, it is shown that the slope of the low-tail of the number of muon distribution measured at the ground is a direct link to the high energy spectrum of neutral pions produced in the interaction of the primary protons. In this presentation, it will also address the experimental feasibility of such measurements and their connection with physical quantities being currently measured at the Large Hadron Collider.

hep-ph↗