Results 21 to 30 of about 10,599 (72)

Steiner t-designs for large t

, 2008
One of the most central and long-standing open questions in combinatorial design theory concerns the existence of Steiner t-designs for large values of t. Although in his classical 1987 paper, L.
A. Betten, A. Delandtsheer, D. Gorenstein, D. Livingstone, D. Pei, D.G. Higman, D.K. Ray-Chaudhuri, D.R. Hughes, D.R. Stinson, D.R. Stinson, F. Buekenhout, F. Buekenhout, G.-C. Rota, H. Lüneburg, H. Wielandt, J. Saxl, J. Tits, J.D. Dixon, J.H. Conway, L. Teirlinck, M. Hall Jr., M. Huber, M. Huber, M. Huber, M. Huber, M.W. Liebeck, M.W. Liebeck, N.D. Tuan, P. Dembowski, P. Kaski, P.J. Cameron, P.J. Cameron, P.J. Cameron, P.J. Cameron, P.J. Cameron, R.A. Fisher, R.E. Block, T.. Beth, W.C. Huffman, W.M. Kantor, W.M. Kantor   +40 more
core   +2 more sources

Normal covering numbers for Sn$S_n$ and An$A_n$ and additive combinatorics

Bulletin of the London Mathematical Society, EarlyView.
Abstract The normal covering number γ(G)$\gamma (G)$ of a noncyclic group G$G$ is the minimum number of proper subgroups whose conjugates cover the group. We give various estimates for γ(Sn)$\gamma (S_n)$ and γ(An)$\gamma (A_n)$ depending on the arithmetic structure of n$n$. In particular we determine the limsups over γ(Sn)/n$\gamma (S_n) / n$ and γ(An)
Sean Eberhard, Connor Mellon
wiley   +1 more source

Studies in the representation theory of finite semigroups

, 1971
. This paper is a continuation of [14], developing the representation theory of finite semigroups further. The main result, Theorem 1.24, states that if the group of units U of a mapping semigroup (Y, S) is multiply transitive with a sufficiently high ...
Y. Zalcstein
semanticscholar   +1 more source

Graphical models for topological groups: A case study on countable Stone spaces

Bulletin of the London Mathematical Society, Volume 57, Issue 8, Page 2311-2335, August 2025.
Abstract By analogy with the Cayley graph of a group with respect to a finite generating set or the Cayley–Abels graph of a totally disconnected, locally compact group, we detail countable connected graphs associated to Polish groups that we term Cayley–Abels–Rosendal graphs.
Beth Branman, George Domat, Hannah Hoganson, Robert Alonzo Lyman   +3 more
wiley   +1 more source

The Dehn twist coefficient for big and small mapping class groups

Journal of the London Mathematical Society, Volume 112, Issue 2, August 2025.
Abstract We study a quasimorphism, which we call the Dehn twist coefficient (DTC), from the mapping class group of a surface (with a chosen compact boundary component) that generalizes the well‐studied fractional Dehn twist coefficient (FDTC) to surfaces of infinite type. Indeed, for surfaces of finite type, the DTC coincides with the FDTC.
Peter Feller, Diana Hubbard, Hannah Turner   +2 more
wiley   +1 more source

On the Terwilliger Algebra of the Group Association Scheme of the Symmetric Group Sym ( 7 )

Journal of Combinatorial Designs, Volume 33, Issue 7, Page 261-274, July 2025.
ABSTRACT Terwilliger algebras are finite‐dimensional semisimple algebras that were first introduced by Paul Terwilliger in 1992 in studies of association schemes and distance‐regular graphs. The Terwilliger algebras of the conjugacy class association schemes of the symmetric groups Sym ( n ), for 3 ≤ n ≤ 6, have been studied and completely determined ...
Allen Herman, Roghayeh Maleki, Andriaherimanana Sarobidy Razafimahatratra   +2 more
wiley   +1 more source

Equivariant geometry of singular cubic threefolds, II

Journal of the London Mathematical Society, Volume 112, Issue 1, July 2025.
Abstract We study linearizability of actions of finite groups on cubic threefolds with nonnodal isolated singularities.
Ivan Cheltsov, Lisa Marquand, Yuri Tschinkel, Zhijia Zhang   +3 more
wiley   +1 more source

Cuntz-Krieger algebras associated with Hilbert $C^*$-quad modules of commuting matrices [PDF]

, 2012
Let ${\cal O}_{{\cal H}^{A,B}_\kappa}$ be the $C^*$-algebra associated with the Hilbert $C^*$-quad module arising from commuting matrices $A,B$ with entries in $\{0,1\}$.
Abstract Let O, Kengo Matsumoto
core  

On the dimension of orthogonal projections of self‐similar measures

Journal of the London Mathematical Society, Volume 112, Issue 1, July 2025.
Abstract Let ν$\nu$ be a self‐similar measure on Rd$\mathbb {R}^d$, d⩾2$d\geqslant 2$, and let π$\pi$ be an orthogonal projection onto a k$k$‐dimensional subspace. We formulate a criterion on the action of the group generated by the orthogonal parts of the iterated function system on π$\pi$, and show that it ensures that the dimension of πν$\pi \nu$ is
Amir Algom, Pablo Shmerkin
wiley   +1 more source