Results 61 to 70 of about 3,053 (239)

On automorphism group of free quadratic extensions over a ring

open access: yesInternational Journal of Mathematics and Mathematical Sciences, 1984
Let R be a ring with 1, ρ an automorphism of R of order 2. Then a normal extension of the free quadratic extension R[x,ρ] with a basis {1,x} over R with an R-automorphism group G is characterized in terms of the element (x−(x)α) for α in G.
George Szeto
doaj   +1 more source

On Galois cohomology and realizability of 2-groups as Galois groups II

open access: yesOpen Mathematics, 2011
Abstract In [Michailov I.M., On Galois cohomology and realizability of 2-groups as Galois groups, Cent. Eur. J. Math., 2011, 9(2), 403–419] we calculated the obstructions to the realizability as Galois groups of 14 non-abelian groups of order 2n, n ≥ 4, having a cyclic subgroup of order 2n−2, over fields containing a primitive 2n−3th ...
openaire   +4 more sources

On the section conjecture over fields of finite type

open access: yesMathematische Nachrichten, Volume 298, Issue 11, Page 3476-3493, November 2025.
Abstract Assume that the section conjecture holds over number fields. We prove then that it holds for a broad class of curves defined over finitely generated extensions of Q$\mathbb {Q}$. This class contains every projective, hyperelliptic curve, every hyperbolic, affine curve of genus ≤2$\le 2$, and a basis of open subsets of any curve.
Giulio Bresciani
wiley   +1 more source

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

open access: yesBulletin of the London Mathematical Society, Volume 57, Issue 11, Page 3307-3325, November 2025.
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

Practice of the Incomplete $p$-Ramification Over a Number Field -- History of Abelian $p$-Ramification

open access: yesCommunications in Advanced Mathematical Sciences, 2019
The theory of $p$-ramification, regarding the Galois group of the maximal pro-$p$-extension of a number field $K$, unramified outside $p$ and $\infty$, is well known including numerical experiments with PARI/GP programs.
Georges Gras
doaj   +1 more source

Arithmetic sparsity in mixed Hodge settings

open access: yesBulletin of the London Mathematical Society, Volume 57, Issue 11, Page 3511-3521, November 2025.
Abstract Let X$X$ be a smooth irreducible quasi‐projective algebraic variety over a number field K$K$. Suppose X$X$ is equipped with a p$p$‐adic étale local system compatible with an admissible graded‐polarized variation of mixed Hodge structures on the complex analytification of XC$X_{\operatorname{\mathbb {C}}}$.
Kenneth Chung Tak Chiu
wiley   +1 more source

Fundamental group of Galois covers of degree 6 surfaces [PDF]

open access: green, 2021
Meirav Amram   +5 more
openalex   +1 more source

The geometry and arithmetic of bielliptic Picard curves

open access: yesJournal of the London Mathematical Society, Volume 112, Issue 5, November 2025.
Abstract We study the geometry and arithmetic of the curves C:y3=x4+ax2+b$C \colon y^3 = x^4 + ax^2 + b$ and their associated Prym abelian surfaces P$P$. We prove a Torelli‐type theorem in this context and give a geometric proof of the fact that P$P$ has quaternionic multiplication by the quaternion order of discriminant 6.
Jef Laga, Ari Shnidman
wiley   +1 more source

A history of Galois fields

open access: yesKhronos, 2016
This paper stresses a specific line of development of the notion of finite field, from Évariste Galois’s 1830 “Note sur la théorie des nombres,” and Camille Jordan’s 1870 Traité des substitutions et des équations algébriques, to Leonard Dickson’s 1901 ...
Frédéric BRECHENMACHER
doaj  

COMPATIBLE SYSTEMS OF GALOIS REPRESENTATIONS ASSOCIATED TO THE EXCEPTIONAL GROUP $E_{6}$

open access: yesForum of Mathematics, Sigma, 2019
We construct, over any CM field, compatible systems of $l$-adic Galois representations that appear in the cohomology of algebraic varieties and have (for all $l$) algebraic monodromy groups equal to the exceptional group of type $E_{6}$.
GEORGE BOXER   +5 more
doaj   +1 more source

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