Results 71 to 80 of about 173,358,856 (223)

Automorphism groups of compact complex surfaces [PDF]

open access: yes, 2021
We study automorphism groups and birational automorphism groups of compactcomplex surfaces. We show that the automorphism group of such surface $X$ isalways Jordan, and the birational automorphism group is Jordan unless $X$ isbirational to a product of ...
Prokhorov, Y., Shramov, C.
core   +1 more source

On Automorphisms of a Distance-Regular Graph with Intersection Array {125,96,1;1,48,125} [PDF]

open access: yesУчёные записки Казанского университета: Серия Физико-математические науки, 2017
J. Koolen posed the problem of studying distance-regular graphs in which neighborhoods of vertices are strongly regular graphs with the second eigenvalue ≤ t for the given positive integer t.
V.V. Bitkina, A.A. Makhnev
doaj  

Characterizing Pyramidal Hadamard Designs With the Largest Number of Fixed Points

open access: yesJournal of Combinatorial Designs, Volume 34, Issue 12, Page 569-573, December 2026.
ABSTRACT A symmetric ( v , k , λ )‐design is said to be f‐pyramidal, with f < v − 1, under the action of a group G if G acts as an automorphism group fixing f points and acting sharply transitively on the remaining ones. We show that, necessarily, f ≤ v − 2 ( k − λ ). In particular, for a Hadamard design with parameters ( v , k , λ ) = ( 4 m − 1 , 2 m −
Tommaso Traetta
wiley   +1 more source

Semicontinuity of the Automorphism Groups of Domains with Rough Boundary

open access: yesInternational Journal of Mathematics and Mathematical Sciences, 2012
Based on some ideas of Greene and Krantz, we study the semicontinuity of automorphism groups of domains in one and several complex variables. We show that semicontinuity fails for domains in , , with Lipschitz boundary, but it holds for domains in with ...
Steven G. Krantz
doaj   +1 more source

On the additive image of zeroth persistent homology

open access: yesTransactions of the London Mathematical Society, Volume 13, Issue 1, December 2026.
Abstract For a category X$X$ and a finite field F$F$, we study the additive image of the functor H0(−;F)∗:rep(X,Top)→rep(X,VectF)$\operatorname{H}_0(-;F)_* \colon \operatorname{rep}(X, \mathbf {Top}) \rightarrow \operatorname{rep}(X, \mathbf {Vect}_F)$, or equivalently, of the free functor rep(X,Set)→rep(X,VectF)$\operatorname{rep}(X, \mathbf {Set ...
Ulrich Bauer   +3 more
wiley   +1 more source

Rational points on even‐dimensional Fermat cubics

open access: yesTransactions of the London Mathematical Society, Volume 13, Issue 1, December 2026.
Abstract We show that even‐dimensional Fermat cubic hypersurfaces are rational over any field of characteristic not equal to three, by constructing explicit rational parameterizations with polynomials of low degree. As a byproduct of our rationality constructions, we obtain estimates for the number of their rational points over a number field and ...
Alex Massarenti
wiley   +1 more source

On the Geometry of the Automorphism Group of a Free Group

open access: yesBulletin of the London Mathematical Society, 1995
The groups \(\Aut(F_3)\) and \(\text{Out}(F_3)\) satisfy strictly exponential isoperimetric inequalities; in particular, they are not automatic. For \(n\geq 3\), \(\Aut(F_n)\) and \(\text{Out}(F_n)\) do not admit bounded bicombings of sub-exponential length, hence they cannot act properly and cocompactly by isometries of any simply-connected space of ...
Bridson, M, Vogtmann, K
openaire   +3 more sources

On the automorphisms of the power semigroups of a numerical semigroup

open access: yesTransactions of the London Mathematical Society, Volume 13, Issue 1, December 2026.
Abstract If H$H$ is a numerical semigroup (i.e., a cofinite subset of the non‐negative integers closed under addition), then the collection of all non‐empty subsets of H$H$ forms a semigroup P(H)$\mathcal {P}(H)$ under the sumset operation induced by addition in H$H$.
Salvatore Tringali, Kerou Wen
wiley   +1 more source

A Note on the Automorphism Group of a p-Group [PDF]

open access: yesProceedings of the American Mathematical Society, 1968
The relation between the order of a p-group and its automorphism group has been the subject of several papers, see [1], [2], and [4]. The existence of outer-automorphisms of a finite p-group was proved by Gaschiitz [3], but the question of the size of the automorphism group of a p-group still remains.
openaire   +1 more source

Context‐free graphs and their transition groups

open access: yesTransactions of the London Mathematical Society, Volume 13, Issue 1, December 2026.
Abstract Starting from context‐free inverse graphs, we introduce a new class of groups and study their structural properties. We establish closure properties, show that their coword problems are context‐free, analyze torsion elements, and realize them as subgroups of the asynchronous rational group.
Daniele D'Angeli   +3 more
wiley   +1 more source

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