Mario Piazza

I am a logician and philosopher with wide-ranging interests. In a roughly descending -- though by no means fixed -- order, these include logical methods in philosophy and artificial intelligence, proof theory for classical and non-classical logics, theory of computation, philosophy of mathematics, epistemology, and ancient philosophy, especially Plato..

My research has been published in many academic journals, including:

The Journal of Symbolic Logic, The Review of Symbolic Logic, Journal of Logic and Computation, Mathematical Structures in Computer Science, Journal of Logic Language and Information, Studia Logica, Journal of Philosophical Logic, Journal of Applied Logic, The Logic Journal of IGPL, Bulletin of the Section of Logic, Synthese, Erkenntnis, European Journal for Philosophy of Science, Foundations of Science, The Cambridge Classical Journal, The Journal of Philosophy, The Australasian Journal of Logic, ACM Transactions on Computational Logic.

Selected recent publications

(You can follow my previous work on ResearchGate)

Proof theory for classical and non classical logics

Fractional semantics, modal logic, and many-valued logics

A Kruskal Procedure for Intuitionistic modal logic IK4, 2026, preprint.
Approximate entailment from classical analytic decomposition, 2026, under review.
An intrinsic additive quotient for classical propositional logic, 2026, under review.
Modal logic with exceptions: taming epistemic possibilities (with M. Tesi), 2025, under review.
Branch-counting conditionals: De Finetti vs. Cooper–Cantwell via fractional semantics, 2025, under review.
An MV-algebra from classical tautologies, draft, 2025.
Cut-free hypersequent calculi for Riesz Łukasiewicz logic (with G. Lenzi), 2025, under review.
Fractional semantics for arithmetic (with G. Massas, M. Tesi), 2025, under review.
Inside classical logic: truth, contradictions, fractionality (with M. Tesi), Studia Logica, 2025.
Fractional-valued modal logic and soft bilateralism (with G. Pulcini and M. Tesi), Bulletin of the Section of Logic, (52/3), 2023, pp. 275–299.
Fractional-valued modal logic (with G. Pulcini, M. Tesi), The Review of Symbolic Logic, 16 (4), 2023, pp. 1033-1052.
Fractional semantics for classical logic (with G. Pulcini), The Review of Symbolic Logic, 13 (4), 2020, pp. 810-828.

Non-monotonic and default logics; normative reasoning

A logic for default deontic reasoning (with A. Sabatini), 2025, under review.
A unified framework for input/output and default logics via hypersequents (with A. Sabatini), Journal of Logic and Computation, 36, (2) 2026, pp. 1-36..
Exception and typicality, logically framed (with M. Tesi), Journal of Logic, Language and Information, 34, 2025, pp. 341-369.
Hypersequent calculi for propositional default logics (with A. Sabatini), ACM Transactions on Computational Logic, 26 (3), 2025, pp. 1-36.
Logical reasoning in social settings (edited book with M. Tesi and P. Vigiani ), Edizioni della Normale, 2025

Refutation calculi and their uses

Refutation calculi for lattice-based logics: from display to tableaux (with A. De Domenico, G. Greco, A. Palmigiano, A. Sabatini), draft 2025. https://arxiv.org/abs/2605.24717.
On anticut rules: classical, FDE-based and intuitionistic logics (with A. Sabatini), The Australasian Journal of Logic, 23 (2) 2026, pp. 109-147.
Linear logic in a refutational setting (with G. Pulcini and M. Tesi), Journal of Logic and Computation, 34 (7) 2024, pp. 1249–1273.
Abduction as deductive saturation: a proof-theoretic inquiry (with G. Pulcini and A. Sabatini), Journal of Philosophical Logic, 52 (6) 2023, pp. 1575–1602.

Proof-theoretic varia

Relevance by decomposition: variable-sharing survives detachment, The Australasian Journal of Logic, 2026, accepted.
Analyticity with extra-logical information (with M. Tesi), Journal of Logic and Computation, 2024 , pp. 1-31.
Non-contractive logics, paradoxes, and multiplicative quantifiers (with C. Nicolai and M. Tesi), The Review of Symbolic Logic, 2023, pp. 1-22.

Theory of computation

Optimal reduction for non-deterministic lambda calculus (with M. Pedicini), draft, 2024.
Abstract machines, optimal reduction, and streams (with A. Lai, M. Pedicini), Mathematical Structures in Computer Science, 29(9) 2019, pp. 1379-1410.

Philosophy of mathematics

Proof Assistants and the Epistemology of Proof. Book under contract with Cambridge University Press.
From Proofs to the Chessboard: Poincaré and Mathematical Understanding, 2026 under review.
The Schematic Price of Reflection, draft 2025.
A Reflection Principle for Kripke-Feferman Truth (with M. Fischer and C. Nicolai), The Journal of Philosophy, 2023, forthcoming
The implicit commitment of arithmetical theories and its semantic core (with C. Nicolai), Erkenntnis, 84 (4), 2019, pp. 913–937.
Truth, Existence and Explanation (ed. with G. Pulcini), Boston Studies in the Philosophy of Science, Springer, 2018.

Epistemology

Why isn't enough, draft, 2024.
What Arrow's information paradox says (to philosophers) (with M. Pedicini), in V. d’Alfonso and D. Berkich, On the Cognitive, Ethical, and Scientific Dimensions of Artificial Intelligence, Springer, 2019, pp. 83-94.

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