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Based on ideas of K\"otter and Kschischang we use constant dimension subspaces as codewords in a network. We show a connection to the theory of q-analogues of a combinatorial designs, which has been studied in Braun, Kerber and Laue as a…

Information Theory · Computer Science 2015-03-17 Andreas-Stephan Elsenhans , Axel Kohnert , Alfred Wassermann

Consider complex semisimple Lie algebras of a given dimension specified by their structure constants. We describe a finite collection of rational functions in the structure constants that form a complete set of invariants: two sets of…

Rings and Algebras · Mathematics 2007-05-23 Vijay Kodiyalam , K. N. Raghavan

Constant dimension codes are subsets of the finite Grassmann variety. The study of these codes is a central topic in random linear network coding theory. Orbit codes represent a subclass of constant dimension codes. They are defined as…

Information Theory · Computer Science 2014-06-20 Joachim Rosenthal , Anna-Lena Trautmann

Constant-dimension codes have recently received attention due to their significance to error control in noncoherent random linear network coding. What the maximal cardinality of any constant-dimension code with finite dimension and minimum…

Information Theory · Computer Science 2010-03-31 Maximilien Gadouleau , Zhiyuan Yan

Cosine-similarity is the cosine of the angle between two vectors, or equivalently the dot product between their normalizations. A popular application is to quantify semantic similarity between high-dimensional objects by applying…

Information Retrieval · Computer Science 2024-03-11 Harald Steck , Chaitanya Ekanadham , Nathan Kallus

As a result of their applications in network coding, space-time coding, and coding for criss-cross errors, matrix codes have garnered significant attention; in various contexts, these codes have also been termed rank-metric codes,…

Information Theory · Computer Science 2015-07-21 Katherine Morrison

Some families of constant dimension codes arising from Riemann-Roch spaces associated to particular divisors of a curve $\X$ are constructed. These families are generalizations of the one constructed by Hansen

Information Theory · Computer Science 2015-08-10 Daniele Bartoli , Matteo Bonini , Massimo Giulietti

In the last years many results in the area of semidefinite programming were obtained for invariant (finite dimensional, or infinite dimensional) semidefinite programs - SDPs which have symmetry. This was done for a variety of problems and…

Optimization and Control · Mathematics 2019-11-07 Christine Bachoc , Dion C. Gijswijt , Alexander Schrijver , Frank Vallentin

Structures of commuting semigroups of isometries under certain additional assumptions like double commutativity or dual double commutativity are found.

Functional Analysis · Mathematics 2023-06-27 Tirthankar Bhattacharyya , Shubham Rastogi , Vijaya Kumar U

The automorphism groups of various linear codes are extensively studied yielding insights into the respective code structure. This knowledge is used in, e.g., theoretical analysis and in improving decoding performance, motivating the…

Information Theory · Computer Science 2024-04-16 Jonathan Mandelbaum , Sisi Miao , Holger Jäkel , Laurent Schmalen

In this review we establish various connections between complex networks and symmetry. While special types of symmetries (e.g., automorphisms) are studied in detail within discrete mathematics for particular classes of deterministic graphs,…

General Finance · Quantitative Finance 2010-11-04 Diego Garlaschelli , Franco Ruzzenenti , Riccardo Basosi

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

Sum-rank codes are an important class of codes which can be utilized for linear network coding, space-time coding and distributed storage. They can not only reduce the size of network alphabet but also detect and correct more errors. Based…

Information Theory · Computer Science 2025-10-14 Qingfeng Xia , Hongwei Liu , Hao Chen , Xu Pan

Knowing the symmetries of a polyhedron can be very useful for the analysis of its structure as well as for practical polyhedral computations. In this note, we study symmetry groups preserving the linear, projective and combinatorial…

A subspace code is defined as a collection of subspaces of an ambient vector space, where each information-encoding codeword is a subspace. This paper studies a class of spatial sensing problems, notably direction of arrival (DoA)…

Signal Processing · Electrical Eng. & Systems 2024-07-04 Hessam Mahdavifar , Robin Rajamäki , Piya Pal

In this note, an intrinsic description of some families of linear codes with symmetries is given, showing that they can be described more generally as quasi group codes, that is, as linear codes allowing a group of permutation automorphisms…

Information Theory · Computer Science 2021-11-11 Martino Borello , Wolfgang Willems

Basic algebraic and combinatorial properties of finite vector spaces in which individual vectors are allowed to have multiplicities larger than $ 1 $ are derived. An application in coding theory is illustrated by showing that multispace…

Information Theory · Computer Science 2024-09-04 Mladen Kovačević

Linear topological spaces with partial ordering (linear kinematics) are studied. They are defined by a set of 8 axioms implying that topology, linear structure and ordering are compatible with each other. Most of the results are valid for…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Victor Revoltovich Krym

We solve the subgraph isomorphism problem in planar graphs in linear time, for any pattern of constant size. Our results are based on a technique of partitioning the planar graph into pieces of small tree-width, and applying dynamic…

Data Structures and Algorithms · Computer Science 2007-05-23 David Eppstein

We study holomorphic isometries between bounded symmetric domains with respect to the Bergman metrics up to a normalizing constant. In particular, we first consider a holomorphic isometry from the complex unit ball into an irreducible…

Complex Variables · Mathematics 2025-04-11 Shan Tai Chan