Results 31 to 40 of about 5,646,983 (176)

A Note on Eigenvalues and Asymmetric Graphs

Axioms, 2023
This note is intended as a contribution to the study of quantitative measures of graph complexity that use entropy measures based on symmetry. Determining orbit sizes of graph automorphism groups is a key part of such studies. Here we focus on an extreme
Abdullah Lotfi, Abbe Mowshowitz, Matthias Dehmer   +2 more
doaj   +1 more source

Normal automorphisms of relatively hyperbolic groups

, 2010
An automorphism of a group G is normal if it fixes every normal subgroup of G setwise. We give an algebraic description of normal automorphisms of relatively hyperbolic groups.
D. Osin, Osin, Denis, Minasyan, Ashot, A. Minasyan   +3 more
core   +1 more source

Compact Manifolds With Unbounded Nilpotent Fundamental Groups and Positive Ricci Curvature

Communications on Pure and Applied Mathematics, EarlyView.
ABSTRACT It follows from the work of Kapovitch and Wilking that a closed manifold with nonnegative Ricci curvature has a uniformly almost nilpotent fundamental group. Leftover questions and conjectures, have asked if in this context the fundamental group is actually uniformly almost abelian. The main goal of this work is to construct examples (Mk9,gk)$(
Elia Bruè, Aaron Naber, Daniele Semola
wiley   +1 more source

Partial Steiner Triple Systems With an Almost Parallel Class Missing Any Given Point

Journal of Combinatorial Designs, EarlyView.
ABSTRACT We say that a hypergraph is factor critical if it has no 1‐factor but deletion of any vertex results in a hypergraph that has a 1‐factor. We show that any factor‐critical hypergraph of order n $n$ has at least n $n$ edges, and that for all integers k > 1 $k\gt 1$ and n > 1 $n\gt 1$ with n ≡ 1 ( mod k ) $n\equiv 1({\rm{mod}}\,k)$ there exists a
Darryn Bryant, Sara Davies, Jack Neubecker   +2 more
wiley   +1 more source

An obstruction to the strong relative hyperbolicity of a group

, 2006
We give a simple combinatorial criterion for a group that, when satisfied, implies the group cannot be strongly relatively hyperbolic. Our criterion applies to several classes of groups, such as surface mapping class groups, Torelli groups, and ...
Javier Aramayona, Aramayona, Javier, James W. Anderson, Anderson, James W., Kenneth J. Shackleton, Shackleton, Kenneth J.   +5 more
core   +1 more source

Unitary $L^{p+}$-representations of almost automorphism groups

Comptes Rendus. Mathématique
Let $G$ be a locally compact group with an open subgroup $H$ with the Kunze–Stein property, and let $\pi $ be a unitary representation of $H$. We show that the representation $\widetilde{\pi }$ of $G$ induced from $\pi $ is an $L^{p+}$-representation if ...
Dabeler, Antje, Mai Elkiær, Emilie, Gerasimova, Maria, de Laat, Tim   +3 more
doaj   +1 more source

Catalan Bounds for Symmetric Strength‐Two Orthogonal Arrays

Journal of Combinatorial Designs, EarlyView.
ABSTRACT A Hamming shell construction is a two‐level array obtained by taking every binary vector of a given Hamming weight a prescribed number of times, for each weight in turn. Such arrays are invariant under all permutations of the factors, and they are strength‐two orthogonal arrays exactly when the multiplicities satisfy three linear constraints ...
Ruwan C. Karunanayaka
wiley   +1 more source

Alternating groups as automorphism groups of Riemann surfaces

, 2006
In this work we give pairs of generators (x, y) for the alternating groups An, 5 ≤ n ≤ 19, such that they determine the minimal genus of a Riemann surface on which An acts as the automorphism group.
Martínez García, Ernesto, Etayo Gordejuela, José Javier   +1 more
core   +1 more source

Topological rigidity of automorphism systems

Nantong Daxue xuebao. Ziran kexue ban
This paper studies the automorphism actions of countable discrete groups on the étale equivalence relations on compact metric spaces. First, the notion of continuous strong orbit equivalence for automorphism systems is introduced and it is proved that ...
QIANG Xiangqi
doaj   +1 more source

Classifying Equidistant Permutation Codes

Journal of Combinatorial Designs, EarlyView.
ABSTRACT A permutation code of length n $n$ is a set of codewords, each of which contains every symbol of a set of size n $n$ exactly once. A permutation code in which any two distinct codewords differ in the same number of coordinates is called equidistant and that number is called the distance.
Patric R. J. Östergård, Luka T. Tolonen   +1 more
wiley   +1 more source