Canadian Mathematical Society
Canadian Mathematical Society
  location:  Publicationsjournals
Search results

Search: MSC category 11 ( Number theory )

  Expand all        Collapse all Results 151 - 175 of 254

151. CJM 2006 (vol 58 pp. 580)

Greither, Cornelius; Kučera, Radan
Annihilators for the Class Group of a Cyclic Field of Prime Power Degree, II
We prove, for a field $K$ which is cyclic of odd prime power degree over the rationals, that the annihilator of the quotient of the units of $K$ by a suitable large subgroup (constructed from circular units) annihilates what we call the non-genus part of the class group. This leads to stronger annihilation results for the whole class group than a routine application of the Rubin--Thaine method would produce, since the part of the class group determined by genus theory has an obvious large annihilator which is not detected by that method; this is our reason for concentrating on the non-genus part. The present work builds on and strengthens previous work of the authors; the proofs are more conceptual now, and we are also able to construct an example which demonstrates that our results cannot be easily sharpened further.

Categories:11R33, 11R20, 11Y40

152. CJM 2006 (vol 58 pp. 643)

Yu, Xiaoxiang
Centralizers and Twisted Centralizers: Application to Intertwining Operators
ABSTRACT The equality of the centralizer and twisted centralizer is proved based on a case-by-case analysis when the unipotent radical of a maximal parabolic subgroup is abelian. Then this result is used to determine the poles of intertwining operators.


153. CJM 2006 (vol 58 pp. 419)

Snaith, Victor P.
Stark's Conjecture and New Stickelberger Phenomena
We introduce a new conjecture concerning the construction of elements in the annihilator ideal associated to a Galois action on the higher-dimensional algebraic $K$-groups of rings of integers in number fields. Our conjecture is motivic in the sense that it involves the (transcendental) Borel regulator as well as being related to $l$-adic \'{e}tale cohomology. In addition, the conjecture generalises the well-known Coates--Sinnott conjecture. For example, for a totally real extension when $r = -2, -4, -6, \dotsc$ the Coates--Sinnott conjecture merely predicts that zero annihilates $K_{-2r}$ of the ring of $S$-integers while our conjecture predicts a non-trivial annihilator. By way of supporting evidence, we prove the corresponding (conjecturally equivalent) conjecture for the Galois action on the \'{e}tale cohomology of the cyclotomic extensions of the rationals.

Categories:11G55, 11R34, 11R42, 19F27

154. CJM 2006 (vol 58 pp. 115)

Ivorra, W.; Kraus, A.
Quelques résultats sur les équations $ax^p+by^p=cz^2$
Let $p$ be a prime number $\geq 5$ and $a,b,c$ be non zero natural numbers. Using the works of K. Ribet and A. Wiles on the modular representations, we get new results about the description of the primitive solutions of the diophantine equation $ax^p+by^p=cz^2$, in case the product of the prime divisors of $abc$ divides $2\ell$, with $\ell$ an odd prime number. For instance, under some conditions on $a,b,c$, we provide a constant $f(a,b,c)$ such that there are no such solutions if $p>f(a,b,c)$. In application, we obtain information concerning the $\Q$-rational points of hyperelliptic curves given by the equation $y^2=x^p+d$ with $d\in \Z$.


155. CJM 2006 (vol 58 pp. 3)

Ben Saïd, Salem
The Functional Equation of Zeta Distributions Associated With Non-Euclidean Jordan Algebras
This paper is devoted to the study of certain zeta distributions associated with simple non-Euclidean Jordan algebras. An explicit form of the corresponding functional equation and Bernstein-type identities is obtained.

Keywords:Zeta distributions, functional equations, Bernstein polynomials, non-Euclidean Jordan algebras
Categories:11M41, 17C20, 11S90

156. CJM 2005 (vol 57 pp. 1155)

Cojocaru, Alina Carmen; Fouvry, Etienne; Murty, M. Ram
The Square Sieve and the Lang--Trotter Conjecture
Let $E$ be an elliptic curve defined over $\Q$ and without complex multiplication. Let $K$ be a fixed imaginary quadratic field. We find nontrivial upper bounds for the number of ordinary primes $p \leq x$ for which $\Q(\pi_p) = K$, where $\pi_p$ denotes the Frobenius endomorphism of $E$ at $p$. More precisely, under a generalized Riemann hypothesis we show that this number is $O_{E}(x^{\slfrac{17}{18}}\log x)$, and unconditionally we show that this number is $O_{E, K}\bigl(\frac{x(\log \log x)^{\slfrac{13}{12}}} {(\log x)^{\slfrac{25}{24}}}\bigr)$. We also prove that the number of imaginary quadratic fields $K$, with $-\disc K \leq x$ and of the form $K = \Q(\pi_p)$, is $\gg_E\log\log\log x$ for $x\geq x_0(E)$. These results represent progress towards a 1976 Lang--Trotter conjecture.

Keywords:Elliptic curves modulo $p$; Lang--Trotter conjecture;, applications of sieve methods
Categories:11G05, 11N36, 11R45

157. CJM 2005 (vol 57 pp. 1215)

Khare, Chandrashekhar
Reciprocity Law for Compatible Systems of Abelian $\bmod p$ Galois Representations
The main result of the paper is a {\em reciprocity law} which proves that compatible systems of semisimple, abelian mod $p$ representations (of arbitrary dimension) of absolute Galois groups of number fields, arise from Hecke characters. In the last section analogs for Galois groups of function fields of these results are explored, and a question is raised whose answer seems to require developments in transcendence theory in characteristic $p$.


158. CJM 2005 (vol 57 pp. 1102)

Weston, Tom
Power Residues of Fourier Coefficients of Modular Forms
Let $\rho \colon G_{\Q} \to \GL_{n}(\Ql)$ be a motivic $\ell$-adic Galois representation. For fixed $m > 1$ we initiate an investigation of the density of the set of primes $p$ such that the trace of the image of an arithmetic Frobenius at $p$ under $\rho$ is an $m$-th power residue modulo $p$. Based on numerical investigations with modular forms we conjecture (with Ramakrishna) that this density equals $1/m$ whenever the image of $\rho$ is open. We further conjecture that for such $\rho$ the set of these primes $p$ is independent of any set defined by Cebatorev-style Galois-theoretic conditions (in an appropriate sense). We then compute these densities for certain $m$ in the complementary case of modular forms of CM-type with rational Fourier coefficients; our proofs are a combination of the Cebatorev density theorem (which does apply in the CM case) and reciprocity laws applied to Hecke characters. We also discuss a potential application (suggested by Ramakrishna) to computing inertial degrees at $p$ in abelian extensions of imaginary quadratic fields unramified away from $p$.

Categories:11F30, 11G15, 11A15

159. CJM 2005 (vol 57 pp. 1080)

Pritsker, Igor E.
The Gelfond--Schnirelman Method in Prime Number Theory
The original Gelfond--Schnirelman method, proposed in 1936, uses polynomials with integer coefficients and small norms on $[0,1]$ to give a Chebyshev-type lower bound in prime number theory. We study a generalization of this method for polynomials in many variables. Our main result is a lower bound for the integral of Chebyshev's $\psi$-function, expressed in terms of the weighted capacity. This extends previous work of Nair and Chudnovsky, and connects the subject to the potential theory with external fields generated by polynomial-type weights. We also solve the corresponding potential theoretic problem, by finding the extremal measure and its support.

Keywords:distribution of prime numbers, polynomials, integer, coefficients, weighted transfinite diameter, weighted capacity, potentials
Categories:11N05, 31A15, 11C08

160. CJM 2005 (vol 57 pp. 812)

Trifković, Mak
On the Vanishing of $\mu$-Invariants of Elliptic Curves over $\qq$
Let $E_{/\qq}$ be an elliptic curve with good ordinary reduction at a prime $p>2$. It has a well-defined Iwasawa $\mu$-invariant $\mu(E)_p$ which encodes part of the information about the growth of the Selmer group $\sel E{K_n}$ as $K_n$ ranges over the subfields of the cyclotomic $\zzp$-extension $K_\infty/\qq$. Ralph Greenberg has conjectured that any such $E$ is isogenous to a curve $E'$ with $\mu(E')_p=0$. In this paper we prove Greenberg's conjecture for infinitely many curves $E$ with a rational $p$-torsion point, $p=3$ or $5$, no two of our examples having isomorphic $p$-torsion. The core of our strategy is a partial explicit evaluation of the global duality pairing for finite flat group schemes over rings of integers.


161. CJM 2005 (vol 57 pp. 449)

Alkan, Emre
On the Sizes of Gaps in the Fourier Expansion of Modular Forms
Let $f= \sum_{n=1}^{\infty} a_f(n)q^n$ be a cusp form with integer weight $k \geq 2$ that is not a linear combination of forms with complex multiplication. For $n \geq 1$, let $$ i_f(n)=\begin{cases}\max\{ i : a_f(n+j)=0 \text{ for all } 0 \leq j \leq i\}&\text{if $a_f(n)=0$,}\\ 0&\text{otherwise}.\end{cases} $$ Concerning bounded values of $i_f(n)$ we prove that for $\epsilon >0$ there exists $M = M(\epsilon,f)$ such that $\# \{n \leq x : i_f(n) \leq M\} \geq (1 - \epsilon) x$. Using results of Wu, we show that if $f$ is a weight 2 cusp form for an elliptic curve without complex multiplication, then $i_f(n) \ll_{f, \epsilon} n^{\frac{51}{134} + \epsilon}$. Using a result of David and Pappalardi, we improve the exponent to $\frac{1}{3}$ for almost all newforms associated to elliptic curves without complex multiplication. Inspired by a classical paper of Selberg, we also investigate $i_f(n)$ on the average using well known bounds on the Riemann Zeta function.


162. CJM 2005 (vol 57 pp. 535)

Kim, Henry H.
On Local $L$-Functions and Normalized Intertwining Operators
In this paper we make explicit all $L$-functions in the Langlands--Shahidi method which appear as normalizing factors of global intertwining operators in the constant term of the Eisenstein series. We prove, in many cases, the conjecture of Shahidi regarding the holomorphy of the local $L$-functions. We also prove that the normalized local intertwining operators are holomorphic and non-vaninishing for $\re(s)\geq 1/2$ in many cases. These local results are essential in global applications such as Langlands functoriality, residual spectrum and determining poles of automorphic $L$-functions.

Categories:11F70, 22E55

163. CJM 2005 (vol 57 pp. 494)

Friedlander, John B.; Iwaniec, Henryk
Summation Formulae for Coefficients of $L$-functions
With applications in mind we establish a summation formula for the coefficients of a general Dirichlet series satisfying a suitable functional equation. Among a number of consequences we derive a generalization of an elegant divisor sum bound due to F.~V. Atkinson.

Categories:11M06, 11M41

164. CJM 2005 (vol 57 pp. 616)

Muić, Goran
Reducibility of Generalized Principal Series
In this paper we describe reducibility of non-unitary generalized principal series for classical $p$-adic groups in terms of the classification of discrete series due to M\oe glin and Tadi\'c.

Categories:22E35, and, 50, 11F70

165. CJM 2005 (vol 57 pp. 328)

Kuo, Wentang; Murty, M. Ram
On a Conjecture of Birch and Swinnerton-Dyer
Let \(E/\mathbb{Q}\) be an elliptic curve defined by the equation \(y^2=x^3 +ax +b\). For a prime \(p, \linebreak p \nmid\Delta =-16(4a^3+27b^2)\neq 0\), define \[ N_p = p+1 -a_p = |E(\mathbb{F}_p)|. \] As a precursor to their celebrated conjecture, Birch and Swinnerton-Dyer originally conjectured that for some constant $c$, \[ \prod_{p \leq x, p \nmid\Delta } \frac{N_p}{p} \sim c (\log x)^r, \quad x \to \infty. \] Let \(\alpha _p\) and \(\beta _p\) be the eigenvalues of the Frobenius at \(p\). Define \[ \tilde{c}_n = \begin{cases} \frac{\alpha_p^k + \beta_p^k}{k}& n =p^k, p \textrm{ is a prime, $k$ is a natural number, $p\nmid \Delta$} . \\ 0 & \text{otherwise}. \end{cases}. \] and \(\tilde{C}(x)= \sum_{n\leq x} \tilde{c}_n\). In this paper, we establish the equivalence between the conjecture and the condition \(\tilde{C}(x)=\mathbf{o}(x)\). The asymptotic condition is indeed much deeper than what we know so far or what we can know under the analogue of the Riemann hypothesis. In addition, we provide an oscillation theorem and an \(\Omega\) theorem which relate to the constant $c$ in the conjecture.

Categories:11M41, 11M06

166. CJM 2005 (vol 57 pp. 267)

Conrad, Keith
Partial Euler Products on the Critical Line
The initial version of the Birch and Swinnerton-Dyer conjecture concerned asymptotics for partial Euler products for an elliptic curve $L$-function at $s = 1$. Goldfeld later proved that these asymptotics imply the Riemann hypothesis for the $L$-function and that the constant in the asymptotics has an unexpected factor of $\sqrt{2}$. We extend Goldfeld's theorem to an analysis of partial Euler products for a typical $L$-function along its critical line. The general $\sqrt{2}$ phenomenon is related to second moments, while the asymptotic behavior (over number fields) is proved to be equivalent to a condition that in a precise sense seems much deeper than the Riemann hypothesis. Over function fields, the Euler product asymptotics can sometimes be proved unconditionally.

Keywords:Euler product, explicit formula, second moment
Categories:11M41, 11S40

167. CJM 2005 (vol 57 pp. 298)

Kumchev, Angel V.
On the Waring--Goldbach Problem: Exceptional Sets for Sums of Cubes and Higher Powers
We investigate exceptional sets in the Waring--Goldbach problem. For example, in the cubic case, we show that all but $O(N^{79/84+\epsilon})$ integers subject to the necessary local conditions can be represented as the sum of five cubes of primes. Furthermore, we develop a new device that leads easily to similar estimates for exceptional sets for sums of fourth and higher powers of primes.

Categories:11P32, 11L15, 11L20, 11N36, 11P55

168. CJM 2005 (vol 57 pp. 338)

Lange, Tanja; Shparlinski, Igor E.
Certain Exponential Sums and Random Walks on Elliptic Curves
For a given elliptic curve $\E$, we obtain an upper bound on the discrepancy of sets of multiples $z_sG$ where $z_s$ runs through a sequence $\cZ=\(z_1, \dots, z_T\)$ such that $k z_1,\dots, kz_T $ is a permutation of $z_1, \dots, z_T$, both sequences taken modulo $t$, for sufficiently many distinct values of $k$ modulo $t$. We apply this result to studying an analogue of the power generator over an elliptic curve. These results are elliptic curve analogues of those obtained for multiplicative groups of finite fields and residue rings.

Categories:11L07, 11T23, 11T71, 14H52, 94A60

169. CJM 2005 (vol 57 pp. 180)

Somodi, Marius
On the Size of the Wild Set
To every pair of algebraic number fields with isomorphic Witt rings one can associate a number, called the {\it minimum number of wild primes}. Earlier investigations have established lower bounds for this number. In this paper an analysis is presented that expresses the minimum number of wild primes in terms of the number of wild dyadic primes. This formula not only gives immediate upper bounds, but can be considered to be an exact formula for the minimum number of wild primes.

Categories:11E12, 11E81, 19F15, 11R29

170. CJM 2004 (vol 56 pp. 897)

Borwein, Jonathan M.; Borwein, David; Galway, William F.
Finding and Excluding $b$-ary Machin-Type Individual Digit Formulae
Constants with formulae of the form treated by D.~Bailey, P.~Borwein, and S.~Plouffe (\emph{BBP formulae} to a given base $b$) have interesting computational properties, such as allowing single digits in their base $b$ expansion to be independently computed, and there are hints that they should be \emph{normal} numbers, {\em i.e.,} that their base $b$ digits are randomly distributed. We study a formally limited subset of BBP formulae, which we call \emph{Machin-type BBP formulae}, for which it is relatively easy to determine whether or not a given constant $\kappa$ has a Machin-type BBP formula. In particular, given $b \in \mathbb{N}$, $b>2$, $b$ not a proper power, a $b$-ary Machin-type BBP arctangent formula for $\kappa$ is a formula of the form $\kappa = \sum_{m} a_m \arctan(-b^{-m})$, $a_m \in \mathbb{Q}$, while when $b=2$, we also allow terms of the form $a_m \arctan(1/(1-2^m))$. Of particular interest, we show that $\pi$ has no Machin-type BBP arctangent formula when $b \neq 2$. To the best of our knowledge, when there is no Machin-type BBP formula for a constant then no BBP formula of any form is known for that constant.

Keywords:BBP formulae, Machin-type formulae, arctangents,, logarithms, normality, Mersenne primes, Bang's theorem,, Zsigmondy's theorem, primitive prime factors, $p$-adic analysis
Categories:11Y99, 11A51, 11Y50, 11K36, 33B10

171. CJM 2004 (vol 56 pp. 673)

Cali, Élie
Défaut de semi-stabilité des courbes elliptiques dans le cas non ramifié
Let $\overline {\Q_2}$ be an algebraic closure of $\Q_2$ and $K$ be an unramified finite extension of $\Q_2$ included in $\overline {\Q_2}$. Let $E$ be an elliptic curve defined over $K$ with additive reduction over $K$, and having an integral modular invariant. Let us denote by $K_{nr}$ the maximal unramified extension of $K$ contained in $\overline {\Q_2}$. There exists a smallest finite extension $L$ of $K_{nr}$ over which $E$ has good reduction. We determine in this paper the degree of the extension $L/K_{nr}$.


172. CJM 2004 (vol 56 pp. 612)

Pál, Ambrus
Solvable Points on Projective Algebraic Curves
We examine the problem of finding rational points defined over solvable extensions on algebraic curves defined over general fields. We construct non-singular, geometrically irreducible projective curves without solvable points of genus $g$, when $g$ is at least $40$, over fields of arbitrary characteristic. We prove that every smooth, geometrically irreducible projective curve of genus $0$, $2$, $3$ or $4$ defined over any field has a solvable point. Finally we prove that every genus $1$ curve defined over a local field of characteristic zero with residue field of characteristic $p$ has a divisor of degree prime to $6p$ defined over a solvable extension.

Categories:14H25, 11D88

173. CJM 2004 (vol 56 pp. 373)

Orton, Louisa
An Elementary Proof of a Weak Exceptional Zero Conjecture
In this paper we extend Darmon's theory of ``integration on $\uh_p\times \uh$'' to cusp forms $f$ of higher even weight. This enables us to prove a ``weak exceptional zero conjecture'': that when the $p$-adic $L$-function of $f$ has an exceptional zero at the central point, the $\mathcal{L}$-invariant arising is independent of a twist by certain Dirichlet characters.

Categories:11F11, 11F67

174. CJM 2004 (vol 56 pp. 356)

Murty, M. Ram; Saidak, Filip
Non-Abelian Generalizations of the Erd\H os-Kac Theorem
Let $a$ be a natural number greater than $1$. Let $f_a(n)$ be the order of $a$ mod $n$. Denote by $\omega(n)$ the number of distinct prime factors of $n$. Assuming a weak form of the generalised Riemann hypothesis, we prove the following conjecture of Erd\"os and Pomerance: The number of $n\leq x$ coprime to $a$ satisfying $$\alpha \leq \frac{\omega(f_a(n)) - (\log \log n)^2/2 }{ (\log \log n)^{3/2}/\sqrt{3}} \leq \beta $$ is asymptotic to $$\left(\frac{ 1 }{ \sqrt{2\pi}} \int_{\alpha}^{\beta} e^{-t^2/2}dt\right) \frac{x\phi(a) }{ a}, $$ as $x$ tends to infinity.

Keywords:Tur{\' a}n's theorem, Erd{\H o}s-Kac theorem, Chebotarev density theorem,, Erd{\H o}s-Pomerance conjecture
Categories:11K36, 11K99

175. CJM 2004 (vol 56 pp. 406)

Pál, Ambrus
Theta Series, Eisenstein Series and Poincaré Series over Function Fields
We construct analogues of theta series, Eisenstein series and Poincar\'e series for function fields of one variable over finite fields, and prove their basic properties.

   1 ... 6 7 8 ... 11    

© Canadian Mathematical Society, 2017 :