1. CMB 2015 (vol 58 pp. 730)
 Efrat, Ido; Matzri, Eliyahu

Vanishing of Massey Products and Brauer Groups
Let $p$ be a prime number and $F$ a field containing a root of
unity of order $p$.
We relate recent results on vanishing of triple Massey products
in the mod$p$ Galois cohomology of $F$,
due to Hopkins, Wickelgren, MinÃ¡Ä, and TÃ¢n, to classical
results in the theory of central simple algebras.
For global fields, we prove a stronger form of the vanishing
property.
Keywords:Galois cohomology, Brauer groups, triple Massey products, global fields Categories:16K50, 11R34, 12G05, 12E30 

2. CMB 2015 (vol 58 pp. 423)
 Yamagishi, Masakazu

Resultants of Chebyshev Polynomials: The First, Second, Third, and Fourth Kinds
We give an explicit formula for the resultant of Chebyshev polynomials of the
first, second, third, and fourth kinds.
We also compute the resultant of modified cyclotomic polynomials.
Keywords:resultant, Chebyshev polynomial, cyclotomic polynomial Categories:11R09, 11R18, 12E10, 33C45 

3. CMB 2015 (vol 58 pp. 225)
 Aghigh, Kamal; Nikseresht, Azadeh

Characterizing Distinguished Pairs by Using Liftings of Irreducible Polynomials
Let $v$ be a henselian valuation of any rank of a field
$K$ and $\overline{v}$ be the unique extension of $v$ to a
fixed algebraic closure $\overline{K}$ of $K$. In 2005, it was studied properties
of those pairs $(\theta,\alpha)$ of elements of $\overline{K}$
with $[K(\theta): K]\gt [K(\alpha): K]$ where $\alpha$ is an element
of smallest degree over $K$ such that
$$
\overline{v}(\theta\alpha)=\sup\{\overline{v}(\theta\beta)
\ \beta\in \overline{K}, \ [K(\beta): K]\lt [K(\theta): K]\}.
$$
Such pairs are referred to as distinguished pairs.
We use the concept of liftings of irreducible polynomials to give a
different characterization of distinguished pairs.
Keywords:valued fields, nonArchimedean valued fields, irreducible polynomials Categories:12J10, 12J25, 12E05 

4. CMB 2014 (vol 57 pp. 538)
 Ide, Joshua; Jones, Lenny

Infinite Families of $A_4$Sextic Polynomials
In this article we develop a test to determine whether a sextic
polynomial that is irreducible over $\mathbb{Q}$ has Galois group isomorphic
to the alternating group $A_4$. This test does not involve the
computation of resolvents, and we use this test to construct several
infinite families of such polynomials.
Keywords:Galois group, sextic polynomial, inverse Galois theory, irreducible polynomial Categories:12F10, 12F12, 11R32, 11R09 

5. CMB 2014 (vol 57 pp. 735)
 Cagliero, Leandro; Szechtman, Fernando

On the Theorem of the Primitive Element with Applications to the Representation Theory of Associative and Lie Algebras
We describe of all finite
dimensional uniserial representations of a commutative associative
(resp. abelian Lie) algebra over a perfect (resp. sufficiently
large perfect) field. In the Lie case the size of the field
depends on the answer to following question, considered and solved
in this paper. Let $K/F$ be a finite separable field extension
and
let $x,y\in K$. When is $F[x,y]=F[\alpha x+\beta y]$ for some
nonzero elements $\alpha,\beta\in F$?
Keywords:uniserial module, Lie algebra, associative algebra, primitive element Categories:17B10, 13C05, 12F10, 12E20 

6. CMB 2011 (vol 55 pp. 233)
 Bishnoi, Anuj; Khanduja, Sudesh K.

On Algebraically Maximal Valued Fields and Defectless Extensions
Let $v$ be a Henselian Krull valuation of a field $K$. In this paper,
the authors give some necessary and sufficient conditions for a
finite simple extension of $(K,v)$ to be defectless. Various
characterizations of algebraically maximal valued fields are also
given which lead to a new proof of a result proved by Yu. L. Ershov.
Keywords:valued fields, nonArchimedean valued fields Categories:12J10, 12J25 

7. CMB 2011 (vol 55 pp. 821)
 PerezGarcia, C.; Schikhof, W. H.

New Examples of NonArchimedean Banach Spaces and Applications
The study carried out in this paper about some new examples of
Banach spaces, consisting of certain valued fields extensions, is
a typical nonarchimedean feature. We determine whether these
extensions are of countable type, have $t$orthogonal bases, or are
reflexive.
As an application we construct, for a class of base fields, a norm
$\\cdot\$ on $c_0$, equivalent to the canonical supremum norm,
without nonzero vectors that are $\\cdot\$orthogonal and such
that there is a multiplication on $c_0$ making $(c_0,\\cdot\)$
into a valued field.
Keywords:nonarchimedean Banach spaces, valued field extensions, spaces of countable type, orthogonal bases Categories:46S10, 12J25 

8. CMB 2009 (vol 40 pp. 81)
 Movahhedi, A.; Salinier, A.

Une caractÃ©risation des corps satisfaisant le thÃ©orÃ¨me de l'axe principal
Resum\'e. On caract\'erise les corps $K$ satisfaisant le th\'eor\`eme
de l'axe principal \`a l'aide de propri\'et\'es des formes
carac\t\'erisation de ces m\^emes corps due \`a Waterhouse,
on retrouve \`a partir de l\`a, de fa\c{c}on \'el\'ementaire,
un r\'esultat de Becker selon lequel un pro$2$groupe qui se
r\'ealise comme groupe de Galois absolu d'un tel corps $K$ est
engendr\'e par des involutions.
ABSTRACT. We characterize general fields $K$, satisfying the
Principal Axis Theorem, by means of properties of trace forms of
the finite extensions of $K$. From this and Waterhouse's
characterization of the same fields, we rediscover, in quite an
elementary way, a result of Becker according to which a
pro$2$group which occurs as the absolute Galois group of such
a field $K$, is generated by
Categories:11E10, 12D15 

9. CMB 2007 (vol 50 pp. 588)
 Labute, John; Lemire, Nicole; Mináč, Ján; Swallow, John

Cohomological Dimension and Schreier's Formula in Galois Cohomology
Let $p$ be a prime and $F$ a field containing a primitive $p$th
root of unity. Then for $n\in \N$, the cohomological dimension
of the maximal pro$p$quotient $G$ of the absolute Galois group
of $F$ is at most $n$ if and only if the corestriction maps
$H^n(H,\Fp) \to H^n(G,\Fp)$ are surjective for all open
subgroups $H$ of index $p$. Using this result, we generalize
Schreier's formula for $\dim_{\Fp} H^1(H,\Fp)$ to $\dim_{\Fp}
H^n(H,\Fp)$.
Keywords:cohomological dimension, Schreier's formula, Galois theory, $p$extensions, pro$p$groups Categories:12G05, 12G10 

10. CMB 2007 (vol 50 pp. 313)
 Tzermias, Pavlos

On CauchyLiouvilleMirimanoff Polynomials
Let $p$ be a prime greater than or equal to 17 and
congruent to
2 modulo 3. We use results of Beukers and Helou on
CauchyLiouvilleMirimanoff
polynomials to show that
the intersection of the Fermat curve of degree $p$ with the
line $X+Y=Z$ in the projective plane
contains no algebraic points of degree
$d$ with $3 \leq d \leq 11$.
We prove a result on
the roots of these polynomials and show that, experimentally,
they seem to satisfy
the conditions of a mild extension of
an irreducibility theorem of P\'{o}lya and Szeg\"{o}.
These conditions are \emph{conjecturally}
also necessary for irreducibility.
Categories:11G30, 11R09, 12D05, 12E10 

11. CMB 2006 (vol 49 pp. 11)
 Bevelacqua, Anthony J.; Motley, Mark J.

GoingDown Results for $C_{i}$Fields
We search for theorems that, given a $C_i$field $K$ and a subfield $k$ of $K$, allow
us to conclude that $k$ is a $C_j$field for some $j$. We give appropriate theorems in
the case $K=k(t)$ and $K = k\llp t\rrp$. We then consider the more difficult case where $K/k$
is an algebraic extension. Here we are able to prove some results, and make conjectures. We
also point out the connection between these questions and Lang's conjecture on nonreal function
fields over a real closed field.
Keywords:$C_i$fields, Lang's Conjecture Categories:12F, 14G 

12. CMB 2006 (vol 49 pp. 113)
13. CMB 2005 (vol 48 pp. 428)
14. CMB 2002 (vol 45 pp. 422)
15. CMB 2002 (vol 45 pp. 388)
 Gille, Philippe

AlgÃ¨bres simples centrales de degrÃ© 5 et $E_8$
As a consequence of a theorem of RostSpringer, we establish that the
cyclicity problem for central simple algebra of degree~5 on fields
containg a fifth root of unity is equivalent to the study of
anisotropic elements of order 5 in the split group of type~$E_8$.
Keywords:algÃ¨bres simples centrales, cohomologie galoisienne Categories:16S35, 12G05, 20G15 

16. CMB 2002 (vol 45 pp. 71)
17. CMB 2001 (vol 44 pp. 313)
 Reverter, Amadeu; Vila, Núria

Images of mod $p$ Galois Representations Associated to Elliptic Curves
We give an explicit recipe for the determination of the images
associated to the Galois action on $p$torsion points of elliptic
curves. We present a table listing the image for all the elliptic
curves defined over $\QQ$ without complex multiplication with
conductor less than 200 and for each prime number~$p$.
Keywords:Galois groups, elliptic curves, Galois representation, isogeny Categories:11R32, 11G05, 12F10, 14K02 

18. CMB 2001 (vol 44 pp. 223)
19. CMB 1999 (vol 42 pp. 354)
 Marshall, Murray A.

A Real Holomorphy Ring without the SchmÃ¼dgen Property
A preordering $T$ is constructed in the polynomial ring $A = \R
[t_1,t_2, \dots]$ (countably many variables) with the following two
properties: (1)~~For each $f \in A$ there exists an integer $N$
such that $N \le f(P) \le N$ holds for all $P \in \Sper_T(A)$.
(2)~~For all $f \in A$, if $N+f, Nf \in T$ for some integer $N$,
then $f \in \R$. This is in sharp contrast with the
Schm\"udgenW\"ormann result that for any preordering $T$ in a
finitely generated $\R$algebra $A$, if property~(1) holds, then
for any $f \in A$, $f > 0$ on $\Sper_T(A) \Rightarrow f \in T$.
Also, adjoining to $A$ the square roots of the generators of $T$
yields a larger ring $C$ with these same two properties but with
$\Sigma C^2$ (the set of sums of squares) as the preordering.
Categories:12D15, 14P10, 44A60 

20. CMB 1998 (vol 41 pp. 214)
21. CMB 1998 (vol 41 pp. 3)
 Anderson, David F.; Dobbs, David E.

Root closure in Integral Domains, III
{If A is a subring of a commutative ring B and if n
is a positive integer, a number of sufficient conditions are given for
``A[[X]]is nroot closed in B[[X]]'' to be equivalent to ``A is nroot
closed in B.'' In addition, it is shown that if S is a multiplicative
submonoid of the positive integers ${\bbd P}$ which is generated by
primes, then there exists a onedimensional quasilocal integral domain
A (resp., a von Neumann regular ring A) such that $S = \{ n \in {\bbd P}\mid
A$ is $n$root closed$\}$ (resp., $S = \{n \in {\bbd P}\mid A[[X]]$
is $n$rootclosed$\}$).
Categories:13G05, 13F25, 13C15, 13F45, 13B99, 12D99 
