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The goal in label-imbalanced and group-sensitive classification is to optimize relevant metrics such as balanced error and equal opportunity. Classical methods, such as weighted cross-entropy, fail when training deep nets to the terminal…

Machine Learning · Computer Science 2021-11-09 Ganesh Ramachandra Kini , Orestis Paraskevas , Samet Oymak , Christos Thrampoulidis

In this paper, we introduced the concept of crossed module for Hom-Lie antialgebras. It is proved that the category of crossed modules for Hom-Lie antialgebras and the category of $Cat^1$-Hom-Lie antialgebras are equivalent to each other.…

Rings and Algebras · Mathematics 2021-02-19 Tao Zhang , Heyu Zhang

Invariance and equivariance to geometrical transformations have proven to be very useful inductive biases when training (convolutional) neural network models, especially in the low-data regime. Much work has focused on the case where the…

Machine Learning · Computer Science 2024-07-11 Mircea Mironenco , Patrick Forré

In this paper, we study deformations of crossed homomorphisms on Lie groups by means of the cohomology which controls them. Using the Moser type argument, we obtain several rigidity results of crossed homomorphisms on Lie groups. We further…

Group Theory · Mathematics 2025-12-16 Jun Jiang

Toroidal Lie algebras are universal central extentions of the finite dimensional simple Lie algbera tensored with Laurent Polynomials in several commuteing variables. In this paper we classify irreducible integrable modules for Toroidal Lie…

Representation Theory · Mathematics 2007-05-23 S. Eswara Rao

We compute the full isometry group of any left invariant metric on a simply connected, non-unimodular Lie group of dimension three. As an application, we determine the index of symmetry of such metrics and prove that the singularities of…

Differential Geometry · Mathematics 2025-03-07 Ana Cosgaya , Silvio Reggiani

We classify Lie-Poisson brackets that are formed from Lie algebra extensions. The problem is relevant because many physical systems owe their Hamiltonian structure to such brackets. A classification involves reducing all brackets to a set…

Mathematical Physics · Physics 2009-10-31 Jean-Luc Thiffeault , P. J. Morrison

The modular symmetries of string loop threshold corrections for gauge coupling constants are studied in the presence of discrete Wilson lines for all examples of abelian orbifolds, where the point group is realised by the action of Coxeter…

High Energy Physics - Theory · Physics 2014-11-18 A. Love , S. Todd

If q : P -> M is a principal K-bundle over the compact manifold M, then any invariant symmetric V-valued bilinear form on the Lie algebra k of K defines a Lie algebra extension of the gauge algebra by a space of bundle-valued 1-forms modulo…

Differential Geometry · Mathematics 2016-09-08 Karl-Hermann Neeb , Christoph Wockel

We address the (pointed) homotopy of crossed module morphisms in modified categories of interest; which generalizes the groups and various algebraic structures. We prove that, the homotopy relation gives rise to an equivalence relation;…

Category Theory · Mathematics 2019-03-13 Kadir Emir , Selim Çetin

In this paper we study the low dimensional cohomology groups of Hom-Lie algebras and their relation with derivations, abelian extensions and crossed modules. On one hand, we introduce the notion of $\alpha$-abelian extensions and we obtain…

Rings and Algebras · Mathematics 2018-02-13 José-Manuel Casas , Xabier García-Martínez

This article concerns linear parts of minimal resolutions of finitely generated modules over commutative local, or graded rings. The focus is on the linearity defect of a module, which marks the point after which the linear part of its…

Commutative Algebra · Mathematics 2021-05-18 Srikanth B. Iyengar , Tim Roemer

A central extension of the loop group of a Lie group is called transgressive, if it corresponds under transgression to a degree four class in the cohomology of the classifying space of the Lie group. Transgressive loop group extensions are…

Differential Geometry · Mathematics 2017-02-01 Konrad Waldorf

In observational causal inference, domain knowledge often leaves multiple covariate adjustments plausible, yet which sets satisfy ignorability is untestable. Different adjustment sets can yield conflicting estimates of the average treatment…

Methodology · Statistics 2026-03-23 Aditya Ghosh , Dominik Rothenhäusler

We prove that an irreducible quasifinite module over the central extension of the Lie algebra of $N\times N$-matrix differential operators on the circle is either a highest or lowest weight module or else a module of the intermediate…

Representation Theory · Mathematics 2007-05-23 Yucai Su

We classify irreducible finite-dimensional modules of a collection of real Lie superalgebras that includes the simple ones, their classical variants, complex Lie superalgebras after restriction of scalars, and all real Lie algebras. Our…

Representation Theory · Mathematics 2026-04-13 Siddhartha Sahi , Hadi Salmasian , Vera Serganova

What are called secondary characteristic classes in Chern-Weil theory are a refinement of ordinary characteristic classes of principal bundles from cohomology to differential cohomology. We consider the problem of refining the construction…

Algebraic Topology · Mathematics 2013-09-30 Domenico Fiorenza , Urs Schreiber , Jim Stasheff

In \cite{BKN} the authors initiated a study of the representation theory of classical Lie superalgebras via a cohomological approach. Detecting subalgebras were constructed and a theory of support varieties was developed. The dimension of a…

Representation Theory · Mathematics 2014-02-26 Brian D. Boe , Jonathan R. Kujawa , Daniel K. Nakano

We show how to integrate a weak morphism of Lie algebra crossed-modules to a weak morphism of Lie 2-groups. To do so we develop a theory of butterflies for 2-term L_infty algebras. In particular, we obtain a new description of the…

Quantum Algebra · Mathematics 2019-02-20 Behrang Noohi

This paper studies differential graded modules and representations up to homotopy of Lie $n$-algebroids, for general $n\in\mathbb{N}$. The adjoint and coadjoint modules are described, and the corresponding split versions of the adjoint and…

Differential Geometry · Mathematics 2020-06-04 Madeleine Jotz Lean , Rajan Amit Mehta , Theocharis Papantonis