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The article contains a detailed proof of the famous Belyi theorem on geometry of complex algebraic curves defined over number fields. It also includes the discussion of several constructions and conjectures inspired by Belyi’s result which where brought up by the first author during his colloquium talks at different universities within the period from 1979 to 1984.

The theory of lattices have shown to be useful in information theory and rotated lattices with high modulation diversity have been extensively studied as an alternative approach for transmission over a Rayleigh-fading channel, where the performance of this modulation schemes essentially depends on the modulation diversity and on the minimum product distance to achieve substantial coding gains. The maximum diversity of a rotated lattice is guaranteed when we use totally real number fields and the minimum product distance is optimized by considering fields with minimum discriminant. In this paper, we present construction of a full diversity rotated lattice for the Rayleigh fading channel in Euclidean space with full diversity, where this construction is through a totally real subfield �� of the cyclotomic field Q ( ζ p ), where p is an odd prime, obtained by endowing their ring of integers.

We propose a notion of functor of points for noncommutative spaces, valued in categories of bimodules, and endowed with an action functional determined by a notion of hermitian structures and height functions, modeled on an interpretation of the classical functor of points as a physical sigma model. We discuss different choices of such height functions, based on different notions of volumes and traces, including one based on the Hattori-Stallings rank. We show that the height function determines a dynamical time evolution on an algebra of observables associated to our functor of points. We focus in particular the case of noncommutative arithmetic curves, where the relevant algebras are sums of matrix algebras over division algebras over number fields, and we discuss a more general notion of noncommutative arithmetic spaces in higher dimensions, where our approach suggests an interpretation of the Jones index as a height function., Comment: 43 pages, LaTeX

Recently, Andreatta, Iovita and Pilloni have constructed spaces of overconvergent modular forms in characteristic p, together with a natural extension of the Coleman-Mazur eigencurve over a compactified (adic) weight space. Similar ideas have also been used by Liu, Wan and Xiao to study the boundary of the eigencurve. This all goes back to an idea of Coleman. In this article, we construct natural extensions of eigenvarieties for arbitrary reductive groups G over a number field which are split at all places above p. If G is GL(2)/Q, then we obtain a new construction of the extended eigencurve of Andreatta-Iovita-Pilloni. If G is an inner form of GL(2) associated to a definite quaternion algebra, our work gives a new perspective on some of the results of Liu-Wan-Xiao. We build our extended eigenvarieties following Hansen's construction using overconvergent cohomology. One key ingredient is a definition of locally analytic distribution modules which permits coefficients of characteristic p (and mixed characteristic). When G is GL(n) over a totally real or CM number field, we also construct a family of Galois representations over the reduced extended eigenvariety., Updated version incorporating a correction to Lemma 2.1.6. The main results are unaffected (after small modifications to some arguments). A separate erratum will be posted on the journal web page

Under an assumption on the existence of p-adic Galois representations, we carry out Taylor--Wiles patching (in the derived category) for the completed homology of the locally symmetric spaces associated to GL(n) over a number field. We use our construction to show that standard conjectures on completed homology imply `big R = big T' theorems. In the case that n=2 and p splits completely in the number field, we relate our construction to the p-adic local Langlands correspondence for GL(2,Q_p)., v2: an issue with the definition of the big Hecke algebra has been fixed. Some other minor changes. v3: slightly weakened the local--global compatibility Conjecture (Conjecture 5.1.12). v4: minor changes, mostly to introduction. v5: fixed an issue in Appendix B, some other minor changes

Several works have characterized weak instances of the Ring-LWE problem by exploring vulnerabilities arising from the use of algebraic structures. Although these weak instances are not addressed by worst-case hardness theorems, enabling other ring instantiations enlarges the scope of possible applications and favors the diversification of security assumptions. In this work, we extend the Ring-LWE problem in lattice-based cryptography to include algebraic lattices, realized through twisted embeddings. We define the class of problems Twisted Ring-LWE, which replaces the canonical embedding by an extended form. By doing so, we allow the Ring-LWE problem to be used over maximal real subfields of cyclotomic number fields. We prove that Twisted Ring-LWE is secure by providing a security reduction from Ring-LWE to Twisted Ring-LWE in both search and decision forms. It is also shown that the twist factor does not affect the asymptotic approximation factors in the worst-case to average-case reductions. Thus, Twisted Ring-LWE maintains the consolidated hardness guarantee of Ring-LWE and increases the existing scope of algebraic lattices that can be considered for cryptographic applications. Additionally, we expand on the results of Ducas and Durmus (Public-Key Cryptography, 2012) on spherical Gaussian distributions to the proposed class of lattices under certain restrictions. As a result, sampling from a spherical Gaussian distribution can be done directly in the respective number field while maintaining its format and standard deviation when seen in Zn via twisted embeddings.

International audience; Consider a smooth, geometrically irreducible, projective curve of genus g ≥ 2 defined over a number field of degree d ≥ 1. It has at most finitely many rational points by the Mordell Conjecture, a theorem of Faltings. We show that the number of rational points is bounded only in terms of g, d, and the Mordell-Weil rank of the curve's Jacobian, thereby answering in the affirmative a question of Mazur. In addition we obtain uniform bounds, in g and d, for the number of geometric torsion points of the Jacobian which lie in the image of an Abel-Jacobi map. Both estimates generalize our previous work for 1-parameter families. Our proof uses Vojta's approach to the Mordell Conjecture, and the key new ingredient is the generalization of a height inequality due to the second-and third-named authors.

We generalize the explicit quadratic Chabauty techniques for integral points on odd degree hyperelliptic curves and for rational points on genus 2 bielliptic curves to arbitrary number fields using restriction of scalars. This is achieved by combining equations coming from Siksek's extension of classical Chabauty with equations defined in terms of p-adic heights attached to independent continuous idele class characters. We give several examples to show the practicality of our methods., Fixed minor issues following the referee's suggestions; 33 pages

Made available in DSpace on 2022-05-01T08:44:37Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-06-01 A construction of laminated lattices of full diversity in odd dimensions d with 3 ≤ d ≤ 15 is presented. The technique, which uses a combination of number fields and error-correcting codes, consists essentially of two steps: In the first, the Abelian number field F of degree d and prime conductor p, where p is a prime congruent to 1 modulo d, is considered. In the second, the lattice is obtained as the canonical embedding (Minkowski homomorphism) of a Z-submodule of OF, the ring of integers of F. The submodule is defined by the parity-check matrices of a Reed–Solomon code over GF(p) and a suitably chosen linear code, typically either binary or over Z/4Z, the ring of integers modulo 4. Department of Mathematics and Statistics San Diego State University Departamento de Matematica Universidade Estadual Paulista Departamento de Matematica Universidade Federal do Ceara Departamento de Matematica Universidade Estadual Paulista

International audience; We prove that the Module Learning With Errors $\mathrm {M\text {-}LWE}$ problem with binary secrets and rank $d$ is at least as hard as the standard version of $\mathrm {M\text {-}LWE}$ with uniform secret and rank $k$, where the rank increases from $d \ge (k+1)\log _2 q + \omega (\log _2 n)$, and the Gaussian noise from $\alpha$ to $\beta = \alpha \cdot \varTheta (n^2\sqrt{d})$, where $n$ is the ring degree and $q$ the modulus. Our work improves on the recent work by Boudgoust et al. in 2020 by a factor of $\sqrt{md}$ in the Gaussian noise, where $m$ is the number of given $\mathrm {M\text {-}LWE}$ samples, when $q$ fulfills some number-theoretic requirements. We use a different approach than Boudgoust et al. to achieve this hardness result by adapting the previous work from Brakerski et al. in 2013 for the Learning With Errors problem to the module setting. Theproof applies to cyclotomic fields, but most results hold for a larger classof number fields, and may be of independent interest.

Let $ K $ be a number field over $ \mathbb{Q} $ and let $ a_K(m) $ denote the number of integral ideals of $ K $ of norm equal to $ m\in\mathbb{N} $. In this paper we obtain asymptotic formulae for sums of the form $ \sum_{m\leq X} a^l_K(m) $ thereby generalizing the previous works on the problem. Previously such asymptotics were known only in the case when $ K $ is Galois or when $K$ was a non normal cubic extension and $ l=2,3 $. The present work subsumes both these cases., 13 Pages

We begin by giving a criterion for a number field $K$ with 2-class group of rank 2 to have a metacyclic Hilbert 2-class field tower, and then we will determine all real quadratic number fields $\mathbb Q(\sqrt d)$ that have a metacyclic nonabelian Hilbert $2$-class field tower.

We define a gap function to measure the difference of two distinct prime ideals in a given number field. In this paper, we determine all quadratic fields and cyclotomic fields satisfying the condition: there exist two distinct prime ideals whose gap is 1.

The ring variant of learning with errors (Ring-LWE) problem has provided efficient post-quantum cryptographic schemes including homomorphic encryption (HE) schemes. Usually, cyclotomic fields are used as underlying number fields of Ring-LWE from the viewpoints of efficiency and security. However, especially in the case of HE schemes, improving the efficiency and ensuring the security are important tasks even now. Arita and Handa proposed to use decomposition fields as underlying number fields of Ring-LWE and successfully constructed a HE scheme which can encrypt many plaintexts efficiently at a time. However, there is no enough evidence that decomposition fields do not provide weak Ring-LWE instances.In this paper, we give an experimental analysis on lattice attacks against Ring-LWE over decomposition fields. More precisely, we conducted lattice attacks against Ring-LWE over decomposition fields and over the l-th cyclotomic fields with some prime numbers l, respectively, and compared each of the running-time, the success rate and the root hermite factor. We also compared the results of the same attacks on various decomposition fields to find decomposition fields providing weak Ring-LWE instances. As a result of our analysis, we expect that decomposition fields would provide more secure and efficient HE schemes based on Ring-LWE compared to the l-th cyclotomic fields.

The Polya group of a number field K is the subgroup of the class group of K generated by the classes of the products of the maximal ideals with same norm. A Polya field is a number field whose Polya group is trivial. Our purpose is to start with known assertions about Polya fields to find results concerning Polya groups. In this second paper we describe the Polya group of some non-Galois extensions of Q . We obtain in particular that the Polya group of a number field ‘chosen at random’ is equal to the whole class group ‘with probability 1’.

Significance In the nineteenth and twentieth centuries, number theorists have intermittently attacked the Fermat equation over number fields, seeking extensions to Kummer’s approach. Nowadays, it is usual to follow in the footsteps of Frey, Serre, Ribet, and Wiles, whose efforts culminated in Wiles’ proof of Fermat’s Last Theorem. Until now, theorems giving a version of Fermat’s Last Theorem over a family of number fields have been marred by a restriction on the class group or the Galois group. In this paper, we prove the asymptotic Fermat’s Last Theorem for some number fields of odd degree, where the restrictions are much milder and local in nature.

We prove an asymptotic formula for the mean-square average of L-functions associated with subgroups of characters of sufficiently large size. Our proof relies on the study of certain character sums ${\mathcal{A}}(p,d)$ recently introduced by E. Elma, where p ≥ 3 is prime and d ≥ 1 is any odd divisor of p − 1. We obtain an asymptotic formula for ${\mathcal{A}}(p,d),$ which holds true for any odd divisor d of p − 1, thus removing E. Elma’s restrictions on the size of d. This answers a question raised in Elma’s paper. Our proof relies on both estimates on the frequency of large character sums and techniques from the theory of uniform distribution. As an application, in the range $1\leq d\leq\frac{\log p}{3\log\log p}$, we obtain a significant improvement $h_{p,d}^- \leq 2(\frac{(1+o(1))p}{24})^{m/4}$ over the trivial bound $h_{p,d}^- \ll (\frac{dp}{24} )^{m/4}$ on the relative class numbers of the imaginary number fields of conductor $p\equiv 1\mod{2d}$ and degree $m=(p-1)/d$, where d ≥ 1 is odd.

In addition to rather complicated general methods it is interesting and valuable to develop fast efficient methods for calculating generators of power integral bases in special types of number fields. We consider sextic fields containing a real cubic and a complex quadratic fields. We develop a very simple and very efficient method to calculate generators of power integral bases in this type of fields. Our method can be applied to infinite families of number fields, as well. We substantially improve the former methods. Our algorithm is illustrated with detailed examples, involving infinite parametric families.

Given fields k ⊆ L , our results concern one parameter L-parametric polynomials over k, and their relation to generic polynomials. The former are polynomials P ( T , Y ) ∈ k [ T ] [ Y ] of group G which parametrize all Galois extensions of L of group G via specialization of T in L, and the latter are those which are L-parametric for every field L ⊇ k . We show, for example, that being L-parametric with L taken to be the single field C ( ( V ) ) ( U ) is in fact sufficient for a polynomial P ( T , Y ) ∈ C [ T ] [ Y ] to be generic. As a corollary, we obtain a complete list of one parameter generic polynomials over a given field of characteristic 0, complementing the classical literature on the topic. Our approach also applies to an old problem of Schinzel: subject to the Birch and Swinnerton-Dyer conjecture, we provide one parameter families of affine curves over number fields, all with a rational point, but with no rational generic point.

Given a number field $K$ of degree $n_K$ and with absolute discriminant $d_K$, we obtain an explicit bound for the number $N_K(T)$ of non-trivial zeros (counted with multiplicity), with height at most $T$, of the Dedekind zeta function $\zeta_K(s)$ of $K$. More precisely, we show that for $T \geq 1$, $$ \Big| N_K (T) - \frac{T}{\pi} \log \Big( d_K \Big( \frac{T}{2\pi e}\Big)^{n_K}\Big)\Big| \le 0.228 (\log d_K + n_K \log T) + 23.108 n_K + 4.520, $$ which improves previous results of Kadiri and Ng, and Trudgian. The improvement is based on ideas from the recent work of Bennett $et$ $al.$ on counting zeros of Dirichlet $L$-functions., Comment: Accepted by Math. Comp

We prove that if a linear group $\Gamma \subset \mathrm{GL}_n(K)$ over a field $K$ of characteristic zero is boundedly generated by semi-simple (diagonalizable) elements then it is virtually solvable. As a consequence, one obtains that infinite $S$-arithmetic subgroups of absolutely almost simple anisotropic algebraic groups over number fields are never boundedly generated. Our proof relies on Laurent's theorem from Diophantine geometry and properties of generic elements., Comment: Final version; to appear in Invent. Math

Let $k$ be a number field. In the spirit of a result by Yongqi Liang, we relate the arithmetic of rational points over finite extensions of $k$ to that of zero-cycles over $k$ for Kummer varieties over $k$. For example, for any Kummer variety $X$ over $k$, we show that if the Brauer-Manin obstruction is the only obstruction to the Hasse principle for rational points on $X$ over all finite extensions of $k$, then the ($2$-primary) Brauer-Manin obstruction is the only obstruction to the Hasse principle for zero-cycles of any given odd degree on $X$ over $k$. We also obtain similar results for products of Kummer varieties, K3 surfaces and rationally connected varieties., 16 pages. Corrected grant reference number and added journal reference and DOI. arXiv admin note: substantial text overlap with arXiv:1804.05819

Higher-dimensional binary shifts of number-theoretic origin with positive topological entropy are considered. We are particularly interested in analysing their symmetries and extended symmetries. They form groups, known as the topological centraliser and normaliser of the shift dynamical system, which are natural topological invariants. Here, our focus is on shift spaces with trivial centralisers, but large normalisers. In particular, we discuss several systems where the normaliser is an infinite extension of the centraliser, including the visible lattice points and the $k$-free integers in some real quadratic number fields., 25 pages, 1 figure; revised version with minor improvements and additions

It is conjectured that within the class group of any number field, for every integer $\ell \geq 1$, the $\ell$-torsion subgroup is very small (in an appropriate sense, relative to the discriminant of the field). In nearly all settings, the full strength of this conjecture remains open, and even partial progress is limited. Significant recent progress toward average versions of the $\ell$-torsion conjecture has crucially relied on counts for number fields, raising interest in how these two types of question relate. In this paper we make explicit the quantitative relationships between the $\ell$-torsion conjecture and other well-known conjectures: the Cohen-Lenstra heuristics, counts for number fields of fixed discriminant, counts for number fields of bounded discriminant (or related invariants), and counts for elliptic curves with fixed conductor. All of these considerations reinforce that we expect the $\ell$-torsion conjecture is true, despite limited progress toward it. Our perspective focuses on the relation between pointwise bounds, averages, and higher moments, and demonstrates the broad utility of the "method of moments.", The paper arXiv:1709.09637v1 by the same authors was submitted for publication in a significantly shorter version; some of the excluded material appears in this new paper, which also proves further results. Version 2 updates some references, with corresponding improvements in Section 6. Version 3 has a few small changes to streamline exposition after referee process

International audience; Let ε be a non-Galois totally real cubic special unit, i.e. a unit such that ε − 1 is also a unit. Then ε and ε − 1 are multiplicatively independent and the unit index j ε of the groups of units generated by −1, ε and ε − 1 in the group of units of the ring of algebraic integers of Q(ε) is finite. It is known that {ε, ε − 1} is a system of fundamental units of the cubic order Z[ε]. V. Ennola conjectured that {ε, ε − 1} is always a system of fundamental units of the maximal order of Q(ε), i.e. that j ε is always equal to 1. Fix an algebraic closure of Q. We prove that for any given prime p there are only finitely many cases for which p divides j ε. We explain how this result makes Ennola's conjecture very reasonable for its possible exceptions would be few and far between. Our proof is conditional: we conjecture that the degrees of some explicit rational fractions that clearly are Laurent polynomials are always negative and given by conjectured explicit formulas. These degrees being easy to compute by using any formal language for algebraic computation, we checked enough of them to obtain that for any given prime p ≤ 1875 there are only finitely many cases for which p divides j ε. We also prove that under the assumption of the ABC conjecture there are only finitely many exceptions to Ennola's conjecture.

Let α 1 , … , α r be algebraic numbers in a number field K generating a subgroup of rank r in K × . We investigate under GRH the number of primes p of K such that each of the orders of ( α i mod p ) lies in a given arithmetic progression associated to α i . We also study the primes p for which the index of ( α i mod p ) is a fixed integer or lies in a given set of integers for each i. An additional condition on the Frobenius conjugacy class of p may be considered. Such results are generalizations of a theorem of Ziegler from 2006, which concerns the case r = 1 of this problem.

We describe the automorphism groups of finite $p$-groups arising naturally via Hessian determinantal representations of elliptic curves defined over number fields. Moreover, we derive explicit formulas for the orders of these automorphism groups for elliptic curves of $j$-invariant $1728$ given in Weierstrass form. We interpret these orders in terms of the numbers of $3$-torsion points (or flex points) of the relevant curves over finite fields. Our work greatly generalizes and conceptualizes previous examples given by du Sautoy and Vaughan-Lee. It explains, in particular, why the orders arising in these examples are polynomial on Frobenius sets and vary with the primes in a nonquasipolynomial manner., 27 pages, minor revisions, including referee's suggestions. To appear in Mathematische Annalen

Let K be a quadratic number field and let \alpha \in K*. We present an explicit finite procedure to compute at once all Kummer degrees [K(\zeta_m,\sqrt[n]{\alpha}):K(\zeta_m)] for n,m \geq 1 with n|m, where \zeta_m denotes a primitive m-th root of unity. We can also replace \alpha by any finitely generated subgroup of K*.

Made available in DSpace on 2021-06-25T10:53:23Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-01-01 In this work, we present the integral trace form TrM/Q(x2) of a cyclic extension M/Q with degree pq, where M = KL, p and q are distinct odd primes, the conductor of M is a square free integer, and x belongs to the ring of algebraic integers OM of M. The integral trace form of M/Q allows one to calculate the packing radius of lattices constructed via the canonical (or twisted) homomorphism of submodules of OM Department of Mathematics São Paulo State University (Unesp) Institute of Biosciences Humanites and Exact Sciences (Ibilce) Campus São José do Rio Preto Department of Mathematics São Paulo State University (Unesp) Institute of Geosciences and Exact Sciences (Igce) Campus Rio Claro Department of Mathematics São Paulo State University (Unesp) Institute of Biosciences Humanites and Exact Sciences (Ibilce) Campus São José do Rio Preto Department of Mathematics São Paulo State University (Unesp) Institute of Geosciences and Exact Sciences (Igce) Campus Rio Claro

A ring $R$ is said to be clean if each element of $R$ can be written as the sum of a unit and an idempotent. $R$ is said to be weakly clean if each element of $R$ is either a sum or a difference of a unit and an idempotent, and $R$ is said to be feebly clean if every element $r$ can be written as $r=u+e_1-e_2$, where $u$ is a unit and $e_1,e_2$ are orthogonal idempotents. Clearly clean rings are weakly clean rings and both of them are feebly clean. In a recent article (J. Algebra Appl. 17 (2018), 1850111(5 pages)), McGoven characterized when the group ring $\mathbb Z_{(p)}[C_q]$ is weakly clean and feebly clean, where $p, q$ are distinct primes. In this paper, we consider a more general setting. Let $K$ be an algebraic number field, $\mathcal O_K$ its ring of integers, $\mathfrak p\subset \mathcal O$ a nonzero prime ideal, and $\mathcal O_{\mathfrak p}$ the localization of $\mathcal O$ at $\mathfrak p$. We investigate when the group ring $\mathcal O_{\mathfrak p}[G]$ is weakly clean and feebly clean, where $G$ is a finite abelian group, and establish an explicit characterization for such a group ring to be weakly clean and feebly clean for the case when $K=\mathbb Q(\zeta_n)$ is a cyclotomic field or $K=\mathbb Q(\sqrt{d})$ is a quadratic field., Comment: To appear in Journal of algebra and its applications

The Kida's formula in classical Iwasawa theory relates the Iwasawa $\lambda$-invariants of $p$-extensions of number fields. Analogue of this formula was subsequently established for the Iwasawa $\lambda$-invariants of Selmer groups under an appropriate $\mu=0$ assumption. In this paper, we give a conceptual (but conjectural) explanation that such a formula should also hold when $\mu\neq 0$. The conjectural component comes from the so-called $\mathfrak{M}_H(G)$-conjecture in noncommutative Iwasawa theory., Comment: 16 pages

Let $A$ be a quaternion algebra over a number field $F$, and $\mathcal{O}$ be an $O_F$-order of full rank in $A$. Let $K$ be a quadratic field extension of $F$ that embeds into $A$, and $B$ be an $O_F$-order in $K$. Suppose that $\mathcal{O}$ is a Bass order that is well-behaved at all the dyadic primes of $F$. We provide a necessary and sufficient condition for $B$ to be optimally spinor selective for the genus of $\mathcal{O}$. This partially generalizes previous results on optimal (spinor) selectivity by C. Maclachlan [Optimal embeddings in quaternion algebras. J. Number Theory, 128(10):2852-2860, 2008] for Eichler orders of square-free levels, and independently by M. Arenas et al. [On optimal embeddings and trees. J. Number Theory, 193:91-117, 2018] and by J. Voight [Chapter 31, Quaternion algebras, volume 288 of Graduate Texts in Mathematics. Springer-Verlag, 2021] for Eichler orders of arbitrary levels., 22 pages, made improvements and corrections, results unchanged

The aim of this paper is to provide an analogue of the Ball-Rivoal theorem for $p$-adic $L$-values of Dirichlet characters. More precisely, we prove for a Dirichlet character $\chi$ and a number field $K$ the formula $\dim_{K}(K+\sum_{i=2}^{s+1} L_p(i,\chi\omega^{1-i}) K )\geq \frac{(1-\epsilon)\log (s)}{2[K:\mathbb{Q}](1+\log 2)}$. As a byproduct, we establish an asymptotic linear independence result for the values of the $p$-adic Hurwitz zeta function., Comment: 26 pages, final version; Duke Math. J. (accepted)

Let $p$ be a fixed odd prime. Let $E$ be an elliptic curve defined over a number field $F$ with good supersingular reduction at all primes above $p$. We study both the classical and plus/minus Selmer groups over the cyclotomic $\mathbb{Z}_p$-extension of $F$. In particular, we give sufficient conditions for these Selmer groups to not contain a non-trivial sub-module of finite index. Furthermore, when $p$ splits completely in $F$, we calculate the Euler characteristics of the plus/minus Selmer groups over the compositum of all $\mathbb{Z}_p$-extensions of $F$ when they are defined.

We derive explicit isomorphisms between certain congruence subgroups of the Siegel modular group, the Hermitian modular group over an arbitrary imaginary-quadratic number field and the modular group over the Hurwitz quaternions of degree 2 and the discriminant kernels of special orthogonal groups S O 0 ( 2 , n ) , n = 3 , 4 , 6 . The proof is based on an application of linear algebra adapted to the number theoretical needs.

Let $P$ and $Q$ be two points on an elliptic curve defined over a number field $K$. For $\alpha\in \text{End}(E)$, define $B_\alpha$ to be the $\mathcal{O}_K$-integral ideal generated by the denominator of $x(\alpha(P)+Q)$. Let $\mathcal{O}$ be a subring of $\text{End}(E)$, that is a Dedekind domain. We will study the sequence $\{B_\alpha\}_{\alpha\in \mathcal{O}}$. We will show that, for all but finitely many $\alpha\in \mathcal{O}$, the ideal $B_\alpha$ has a primitive divisor when $P$ is a non-torsion point and there exist two endomorphisms $g\neq 0$ and $f$ so that $f(P)=g(Q)$. This is a generalization of previous results on elliptic divisibility sequences., Comment: Minor changes. Final version of the paper. Published in Research in Number Theory

Let $K$ be a number field. Given a polynomial $f(x)\in K[x]$ of degree $d\ge 2$, it is conjectured that the number of preperiodic points of $f$ is bounded by a uniform bound that depends only on $d$ and $[K:\mathbb Q]$. However, the only examples of parametric families of polynomials with no preperiodic points are known when $d$ is divisible by either $2$ or $3$ and $K=\mathbb Q$. In this article, given any integer $d\ge 2$, we display infinitely many parametric families of polynomials of the form $f_t(x)=x^d+c(t)$, $c(t)\in K(t)$, with no rational preperiodic points for any $t\in K$.

The main aim of the present paper is to disprove the Cohen--Lenstra--Martinet heuristics in two different ways and to offer possible corrections. We also recast the heuristics in terms of Arakelov class groups, giving an explanation for the probability weights appearing in the general form of the heuristics. We conclude by proposing a rigorously formulated Cohen--Lenstra--Martinet conjecture., Comment: Expanded introduction, and other minor improvements in the exposition, 31 pages. Final version, to appear in Proc. London Math. Soc

An iterated tower of number fields is constructed by adding preimages of a base point by iterations of a rational map. A certain basic quadratic rational map defined over the Gaussian number field yields such a tower of which any two steps are relative bicyclic biquadratic extensions. Regarding such towers as analogues of $\mathbf{Z}_{2}$-extensions, we examine the parity of 2-ideal class numbers along the towers with some examples.

Some important properties of lattices are packing density and full diversity, which may be good for signal transmission over both Gaussian and Rayleigh fading channel, respectively. The algebraic lattices are constructed through twisted homomorphism of some modules in the ring of integers of a number field \begin{document}$ \mathbb{K} $\end{document}. In this paper, we present a construction of some families of rotated \begin{document}$ A_n- $\end{document}lattices, for \begin{document}$ n = 2^{r-2}-1 $\end{document}, \begin{document}$ r \geq 4 $\end{document}, via totally real subfield of cyclotomic fields. Furthermore, closed-form expressions for the minimum product distance of those lattices are obtained through algebraic properties.

We extend the lifting methods of our previous paper to lift reducible odd representations $\bar{\rho}:\mathrm{Gal}(\overline{F}/F) \to G(k)$ of Galois groups of global fields $F$ valued in Chevalley groups $G(k)$. Lifting results, when combined with automorphy lifting results pioneered by Wiles in the number field case and the results on the global Langlands correspondence proved by Drinfeld and L. Lafforgue in the function field case, give the only known method to access modularity of mod $p$ Galois representations in both reducible and irreducible cases. In the reducible case this allows one to show that the actual representation, rather than just its semisimplification, arises from reduction of the geometric representation attached to a cuspidal automorphic representation on the dual group of $G$. As a particularly concrete application, we get a version of Serre's modularity conjecture for reducible, odd representations $\bar{\rho}: \mathrm{Gal}(\overline{\mathbb{Q}}/\mathbb{Q}) \to \mathrm{GL}_2(k)$. This extends earlier results of Hamblen and Ramakrishna in this classical case and proves modularity of infinitely many extensions of fixed characters that are not covered by loc. cit., Comment: Some clarifications and corrections following referee report. Final version, to appear in Invent. Math

Let A be the product of an abelian variety and a torus over a number field K, and let $$m \ge 2$$ be a square-free integer. If $\alpha \in A(K)$ is a point of infinite order, we consider the set of primes $\mathfrak p$ of K such that the reduction $(\alpha \bmod \mathfrak p)$ is well defined and has order coprime to m. This set admits a natural density, which we are able to express as a finite sum of products of $\ell$ -adic integrals, where $\ell$ varies in the set of prime divisors of m. We deduce that the density is a rational number, whose denominator is bounded (up to powers of m) in a very strong sense. This extends the results of the paper Reductions of points on algebraic groups by Davide Lombardo and the second author, where the case m prime is established.