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The concept of a Kleene algebra (sometimes also called Kleene lattice) was already generalized by the first author for non-distributive lattices under the name pseudo-Kleene algebra. We extend these concepts to posets and show how…

Rings and Algebras · Mathematics 2020-06-09 Ivan Chajda , Helmut Länger

A general position map $f:K\to M$ of a $k$-dimensional simplicial complex to a $2k$-dimensional manifold (for $k=1$, of a graph to a surface) is a $\mathbb Z_2$-embedding if $|f\sigma \cap f\tau|$ is even for any non-adjacent $k$-faces…

Geometric Topology · Mathematics 2026-02-27 A. Skopenkov , O. Styrt

We define the notion of a partially additive Kleene algebra, which is a Kleene algebra where the + operation need only be partially defined. These structures formalize a number of examples that cannot be handled directly by Kleene algebras.…

Logic in Computer Science · Computer Science 2007-05-23 Riccardo Pucella

Partial Combinatory Algebras (PCAs) provide a foundational model of the untyped $\lambda$-calculus and serve as the basis for many notions of computability, such as realizability theory. However, PCAs support a very limited notion of…

Logic in Computer Science · Computer Science 2025-06-12 Liron Cohen , Ariel Grunfeld , Dominik Kirst , Étienne Miquey

This paper investigates the logical strength of completeness theorems for modal propositional logic within second-order arithmetic. We demonstrate that the weak completeness theorem for modal propositional logic is provable in…

Logic · Mathematics 2025-03-04 Sho Shimomichi , Yuto Takeda , Keita Yokoyama

We introduce partially observable concurrent Kleene algebra (POCKA), an algebraic framework to reason about concurrent programs with control structures, such as conditionals and loops. POCKA enables reasoning about programs that can access…

Logic in Computer Science · Computer Science 2023-02-06 Jana Wagemaker , Paul Brunet , Simon Docherty , Tobias Kappé , Jurriaan Rot , Alexandra Silva

Concurrent Kleene Algebra (CKA) extends basic Kleene algebra with a parallel composition operator, which enables reasoning about concurrent programs. However, CKA fundamentally misses tests, which are needed to model standard programming…

Logic in Computer Science · Computer Science 2023-02-03 Tobias Kappé , Paul Brunet , Alexandra Silva , Jana Wagemaker , Fabio Zanasi

In this paper we analyze the connection between some properties of partially strongly compact cardinals: the completion of filters of certain size and instances of the compactness of $\mathcal{L}_{\kappa,\kappa}$. Using this equivalence we…

Logic · Mathematics 2018-09-18 Yair Hayut

Kirchberg's Embedding Problem (KEP) asks whether every separable C$^*$ algebra embeds into an ultrapower of the Cuntz algebra $\mathcal{O}_2$. In this paper, we use model theory to show that this conjecture is equivalent to a local…

Operator Algebras · Mathematics 2015-03-02 Isaac Goldbring , Thomas Sinclair

We deal with (< kappa)-supported iterated forcing notions which are (E_0,E_1)-complete, have in mind problems on Whitehead groups, uniformizations and the general problem. We deal mainly with the successor of a singular case. This continues…

Logic · Mathematics 2016-09-07 Saharon Shelah

The Kirchberg Embedding Problem (KEP) asks if every C*-algebra embeds into an ultrapower of the Cuntz algebra $\mathcal{O}_2$. In an effort to provide a negative solution to the KEP and motivated by the recent refutation of the Connes…

Logic · Mathematics 2023-03-07 Alec Fox , Isaac Goldbring , Bradd Hart

The Kirchberg Embedding Problem (KEP) asks if every C*-algebra embeds into an ultrapower of the Cuntz algebra $\cal O_2$. Motivated by the recent refutation of the Connes Embedding Problem using the quantum complexity result MIP*=RE, we…

Operator Algebras · Mathematics 2023-03-03 Isaac Goldbring , Bradd Hart

Kleene algebra (KA) is the algebra of regular events. Familiar examples of Kleene algebras include regular sets, relational algebras, and trace algebras. A Kleene algebra with tests (KAT) is a Kleene algebra with an embedded Boolean…

Logic · Mathematics 2008-01-16 James Worthington

We extend the formalisation of confluence results in Kleene algebras to a formalisation of coherent confluence proofs. For this, we introduce the structure of higher globular Kleene algebra, a higher-dimensional generalisation of modal and…

Logic in Computer Science · Computer Science 2023-06-22 Cameron Calk , Eric Goubault , Philippe Malbos , Georg Struth

We consider Kleene and Stone algebras defined on the completion DM(RS) of the ordered set of rough sets induced by a reflexive relation. We focus on cases where the completion forms a spatial and completely distributive lattice. We derive…

Rings and Algebras · Mathematics 2026-04-17 Jouni Järvinen , Sándor Radeleczki

Answering some of the main questions from [MR13], we show that whenever $\kappa$ is a cardinal satisfying $\kappa^{< \kappa} = \kappa > \omega$, then the embeddability relation between $\kappa$-sized structures is strongly invariantly…

Logic · Mathematics 2021-02-18 Filippo Calderoni , Heike Mildenberger , Luca Motto Ros

We determine all composition-closed equational classes of Boolean functions. These classes provide a natural generalization of clones and iterative algebras: they are closed under composition, permutation and identification…

Rings and Algebras · Mathematics 2011-02-23 Tamás Waldhauser

We study group algebras for compact groups in the category of real and complex weakly complete vector spaces. We also show that the group algebra is a quotient of the weakly complete universal enveloping algebra of the Lie algebra of the…

Group Theory · Mathematics 2019-11-18 Karl Heinrich Hofmann , Linus Kramer

In the present paper, we introduce a multi-type calculus for the logic of measurable Kleene algebras, for which we prove soundness, completeness, conservativity, cut elimination and subformula property. Our proposal imports ideas and…

Logic · Mathematics 2018-05-22 Giuseppe Greco , Fei Liang , Alessandra Palmigiano

We give a $K$-theoretic realization of all affine Hecke algebras with two unequal parameters including exceptional types. This extends the celebrated work of Kazhdan and Lusztig, who gave a $K$-theoretic realization of affine Hecke algebras…

Representation Theory · Mathematics 2025-05-13 Jonas Antor