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We modify the definition of spherical knotoids to include a framing, in analogy to framed knots, and define a further modification that includes a secondary 'coframing' to obtain 'biframed' knotoids. We exhibit topological spaces whose…

Geometric Topology · Mathematics 2022-06-22 Wout Moltmaker

This paper introduces a notion of presentation for locally inverse semigroups and develops a graph structure to describe the elements of locally inverse semigroups given by these presentations. These graphs will have a role similar to the…

Group Theory · Mathematics 2021-12-22 Luís Oliveira

In this paper we characterize the projective modules over an arbitrary quantale, and then we apply such a characterization in order to define the K_0 group of a quantale. Then we study congruences of quantales and quantale modules by means…

Logic · Mathematics 2017-06-20 Ciro Russo

We provide a unified treatment of several results concerning full groups of ample groupoids and paradoxical decompositions attached to them. This includes a criterion for the full group of an ample groupoid being amenable as well as…

Operator Algebras · Mathematics 2026-04-28 Vadim Alekseev , Martin Finn-Sell

Quantum groups have been widely explored as a tool to encode possible nontrivial generalisations of reference frame transformations, relevant in quantum gravity. In quantum information, it was found that the reference frames can be…

Let $\Gamma$ be a discrete finitely generated group. Let $\hat{M}\to T$ be a $\Gamma$-equivariant fibration, with fibers diffeomorphic to a fixed even dimensional manifold with boundary $Z$. We assume that $\Gamma\to \hat{M}\to…

Differential Geometry · Mathematics 2007-05-23 Eric Leichtnam , Paolo Piazza

We present a higher index theorem for a certain class of etale one-dimensional complex-analytic groupoids. The novelty is the use of the local anomaly formula established in a previous paper, which represents the bivariant Chern character…

K-Theory and Homology · Mathematics 2009-06-12 Denis Perrot

We fix a path model for the space of filters of the inverse semigroup $\mathcal{S}_\Lambda$ associated to a left cancellative small category $\Lambda$. Then, we compute its tight groupoid, thus giving a representation of its $C^*$-algebra…

Operator Algebras · Mathematics 2019-06-19 Eduard Ortega , Enrique Pardo

The quantum completion of the space of connections in a manifold can be seen as the set of all morphisms from the groupoid of the edges of the manifold to the (compact) gauge group. This algebraic construction generalizes an analogous…

High Energy Physics - Theory · Physics 2015-06-25 J. M. Velhinho

It is well-known that a knot in a contact manifold $(M,C)$ transverse to a trivialized contact structure possesses the natural framing given by the first of the trivialization vectors along the knot. If the Euler class $e_C\in H^2(M)$ of…

Symplectic Geometry · Mathematics 2007-05-23 Vladimir Chernov

We start by reviewing the relation between toposes and Grothendieck quantales. We improve results of previous work on this relation by giving both a characterisation of the map from the tensor product of two internal sup-lattices to another…

Category Theory · Mathematics 2013-11-15 Simon Henry

Let $\mathsf{Q}$ be a commutative and unital quantale. By a $\mathsf{Q}$-map we mean a left adjoint in the quantaloid of sets and $\mathsf{Q}$-relations, and by a partial $\mathsf{Q}$-map we refer to a Kleisli morphism with respect to the…

Category Theory · Mathematics 2025-05-14 Lili Shen , Xiaoye Tang

Formal orbifolds are defined in higher dimension. Their \'etale fundamental groups are also defined. It is shown that the fundamental groups of formal orbifolds have certain finiteness property and it is also shown that they can be used to…

Algebraic Geometry · Mathematics 2017-06-02 Manish Kumar

We present some homological properties of a relation $\beta$ on ordered groupoids that generalises the minimum group congruence for inverse semigroups. When $\beta$ is a transitive relation on an ordered groupoid $G$, the quotient $G /…

Group Theory · Mathematics 2017-04-13 B. O. Bainson , N. D. Gilbert

The notion of local equivalence relation on a topological space is generalised to that of local subgroupoid. The main result is the construction of the holonomy and monodromy groupoids of certain Lie local subgroupoids, and the formulation…

Differential Geometry · Mathematics 2007-05-23 Ronald Brown , Ilhan Içen

By restricting to a class of localic open groupoids $G$ which, similarly to Lie groupoids, possess appropriate covers $\widehat G\to G$ by \'etale groupoids, we extend results about groupoid actions and quantales that were previously proved…

Category Theory · Mathematics 2020-09-23 Juan Pablo Quijano , Pedro Resende

The classical theory of invariant means, which plays an important role in the theory of paradoxical decompositions, is based upon what are usually termed `pseudogroups'. Such pseudogroups are in fact concrete examples of the Boolean inverse…

Category Theory · Mathematics 2015-03-13 Ganna Kudryavtseva , Mark V. Lawson , Daniel H. Lenz , Pedro Resende

We study the local isomorphism classes, also known as genera or weak equivalence classes, of fractional ideals of orders in \'etale algebras. We provide a classification in terms of linear algebra objects over residue fields. As a…

Number Theory · Mathematics 2025-03-17 Stefano Marseglia

We give a new characterization of partial groups as a subcategory of symmetric (simplicial) sets. This subcategory has an explicit reflection, which permits one to compute colimits in the category of partial groups. We also introduce the…

Group Theory · Mathematics 2025-03-10 Philip Hackney , Justin Lynd

We investigate various groupoids associated to an arbitrary inverse semigroup with zero. We show that the groupoid of filters with respect to the natural partial order is isomorphic to the groupoid of germs arising from the standard action…

Rings and Algebras · Mathematics 2022-06-06 Becky Armstrong , Lisa Orloff Clark , Astrid an Huef , Malcolm Jones , Ying-Fen Lin