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We record a particularly simple construction on top of Lumsdaine's local universes that allows for a Coquand-style universe of propositions with propositional extensionality to be interpreted in a category with subobject classifiers.

Logic in Computer Science · Computer Science 2024-05-24 Xu Huang

A class of transformations of $R_q$-matrices is introduced such that the $q\to 1$ limit gives explicit nonstandard $R_{h}$-matrices. The transformation matrix is singular itself at $q\to 1$ limit. For the transformed matrix, the…

q-alg · Mathematics 2009-10-30 B. Abdesselam , A. Chakrabarti , R. Chakrabarti

We introduce a new class of infinite-dimensional Lie algebras, which we refer to as continuum Kac-Moody algebras. Their construction is closely related to that of usual Kac-Moody algebras, but they feature a continuum root system with no…

Representation Theory · Mathematics 2022-07-19 Andrea Appel , Francesco Sala , Olivier Schiffmann

Let $P,$ $S,$ and $T$ be semigroups, $f:P\to S$ and $g:P\to T$ semigroup homomorphisms, and $X$ a generating set for $S$ (possibly infinite). Clearly, a <i>necessary</i> condition for there to exist a homomorphism $S\to T$ making a…

Group Theory · Mathematics 2026-03-24 George M. Bergman

In this paper we have found a necessary and sufficient condition for equivalence of two norms on a linear space using the theory of exponential vector space. Exponential vector space is an ordered algebraic structure which can be considered…

Functional Analysis · Mathematics 2023-05-23 Dhruba Prakash Biswas , Priti Sharma , Sandip Jana

Motivated by conjectures relating group orderability, Floer homology, and taut foliations, we discuss a systematic and broadly applicable technique for constructing left-orders on the fundamental groups of rational homology 3-spheres.…

Geometric Topology · Mathematics 2018-03-28 Marc Culler , Nathan M. Dunfield

A nonconforming linear element method is developed for a three-dimensional generalized tensor-valued Stokes equation associated with the Hessian complex in this paper. A discrete Helmholtz decomposition for the piecewise constant space of…

Numerical Analysis · Mathematics 2025-10-28 Ziwen Gu , Xuehai Huang

In this paper, we define the \textit{normal form} of collections of disjoint three \textit{bridge arcs} for a given rational $3$-tangle. We show that there is a sequence of \textit{normal jump moves} which leads one to the other for two…

Geometric Topology · Mathematics 2023-03-15 Bo-hyun Kwon , Jung Hoon Lee

In this paper, we use geometric tools to study the structure of asymptotic expanders and show that a sequence of asymptotic expanders always admits a "uniform exhaustion by expanders". It follows that asymptotic expanders cannot be coarsely…

Metric Geometry · Mathematics 2021-10-06 Ana Khukhro , Kang Li , Federico Vigolo , Jiawen Zhang

Asymptotic expansions for generalised trigonometric integrals are obtained in terms of elementary functions, which are valid for large values of the parameter $a$ and unbounded complex values of the argument. These follow from new…

Classical Analysis and ODEs · Mathematics 2025-08-11 T. M. Dunster

The method of alternating projections (MAP) is a common method for solving feasibility problems. While employed traditionally to subspaces or to convex sets, little was known about the behavior of the MAP in the nonconvex case until 2009,…

Functional Analysis · Mathematics 2012-05-03 Heinz H. Bauschke , D. Russell Luke , Hung M. Phan , Xianfu Wang

This article describes an entirely algebraic construction for developing conformal geometries, which provide models for, among others, the Euclidean, spherical and hyperbolic geometries. On one hand, their relationship is usually shown…

Metric Geometry · Mathematics 2018-07-13 Máté Lehel Juhász

Let $R$ be a left-symmetric conformal algebra and $Q$ be a $\mathbb{C}[\partial]$-module. We introduce the notion of a unified product for left-symmetric conformal algebras and apply it to construct an object $\mathcal{H}^2_R(Q,R)$ to…

Rings and Algebras · Mathematics 2023-04-12 Zhongyin Xu , Yanyong Hong

In this article, we present two methods to construct 2-uninorms on bounded lattices by using additive generators, which are further used for inducing uninorms, nullnorms, uni-nullnorms and null-uninorms, respectively. We also provide some…

Rings and Algebras · Mathematics 2022-12-01 Shudi Liang , Xue-ping Wang

A linear extension of a poset $P$ is a permutation of the elements of the set that respects the partial order. Let $L(P)$ denote the number of linear extensions. It is a #P complete problem to determine $L(P)$ exactly for an arbitrary…

Probability · Mathematics 2017-07-03 Jacqueline Banks , Scott Garrabrant , Mark L. Huber , Anne Perizzolo

We obtain some "universal" estimates for $L_2$-norm of the solution of a parabolic equation via a weighted version of $H^{-1}$-norm of the free term. More precisely, we found the limit upper estimate that can be achieved by transformation…

Analysis of PDEs · Mathematics 2008-05-09 Nikolai Dokuchaev

We say that a ring $R$ is t-unital if the natural map $R\otimes_RR\rightarrow R$ is an isomorphism, and a left $R$-module $P$ is c-unital if the natural map $P\rightarrow\operatorname{Hom}_R(R,P)$ is an isomorphism. For a t-unital ring $R$,…

Rings and Algebras · Mathematics 2023-10-05 Leonid Positselski

We give a new completion for the quasi-uniform spaces. We call the whole procedure {\it $\tau$-completion} and the new space {\it $\tau$-complement of the given}. The basic result is that every $T_{_0}$ quasi-uniform space has a…

General Topology · Mathematics 2010-08-10 Athanasios Andrikopoulos , John Stabakis

Many kinds of categorical structure require the existence of finite limits, of colimits of some specified type, and of "exactness" conditions between the finite limits and the specified colimits. Some examples are the notions of regular, or…

Category Theory · Mathematics 2012-02-20 Richard Garner , Stephen Lack

The problem of finding optimal curves (the longest arcs) for sub-Lorentzian structures is an optimal control problem with an unbounded control set and a concave cost functional. The question of existence of an optimal solution is nontrivial…

Differential Geometry · Mathematics 2026-03-10 A. V. Podobryaev
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