Effective Approximation to Complex Algebraic Numbers by Algebraic Numbers of Bounded Degree
Prajeet Bajpai, Yann Bugeaud
备注:
Updated with corrections, in particular to the statement and proof of Thm 2.4. Presentation of proofs is also considerably improved following referee feedback. Final version, appears in Trans. AMS
We establish the first effective improvements on the Liouville inequality for approximation to complex non-real algebraic numbers by complex algebraic numbers of degree at most 4.
The degree sequence of the algebraic numbers in an algebraic linear recurrence sequence is shown to be virtually periodic. This is proved using the Skolem-Mahler-Lech theorem. It has applications to the degree sequence and the minimal polynomial sequence for exponential sums over finite fields. The degree periodicity also holds for some more complicated non-linear recurrence sequences. We give one example from the iterations of a polynomial map. This depending on the dynamic Mordell-Lang conjecture which has been proved in some cases.
Given a number field $L$, we define the degree of an algebraic number $v \in L$ with respect to a choice of a primitive element of $L$. We propose the question of computing the minimal degrees of algebraic numbers in $L$, and examine these values in degree $4$ Galois extensions over $\mathbb{Q}$ and triquadratic number fields. We show that computing minimal degrees of non-rational elements in triquadratic number fields is closely related to solving classical Diophantine problems such as congruent number problem as well as understanding various arithmetic properties of elliptic curves.
Let $f(x)$ be an irreducible polynomial with integer coefficients of degree at least two. Hooley proved that the roots of the congruence equation $f(x)\equiv 0\mod n$ is uniformly distributed. as a parallel of Hooley's theorem under ideal theoretical setting, we prove the uniformity of the distribution of residues of an algebraic number modulo degree one ideals. Then using this result we show that the roots of a system of polynomial congruences are uniformly distributed. Finally, the distribution of digits of n-adic expansions of an algebraic number is discussed.
Let $N_n(X)$ denote the number of degree $n$ number fields with discriminant bounded by $X$. In this note, we improve the best known upper bounds on $N_n(X)$, finding that $N_n(X) = O(X^{ c (\log n)^2})$ for an explicit constant $c$.
Diagonals and algebraicity modulo $p$: a sharper degree bound
Univ. Claude Bernard Lyon 1(里昂第一大学);CNRS UMR 5208, Institut Camille Jordan(法国国家科学研究中心联合研究单位5208,卡米尔·若尔当研究所);Centre International de Rencontres Mathématiques (CIRM)(国际数学相遇中心);Inria(法国国家信息与自动化研究所);Sorbonne Université(索邦大学);LIP6(计算机实验室6);CNRS(法国国家科学研究中心);IMB(布尔巴基数学研究所);Université de Bordeaux(波尔多大学)
设a和b是代数数数,使得a和b中恰好有一个是代数整数,设f_t(z):=z^2+t是一族以t为参数的多项式。证明了存在正整数m和n使得ft ^m(a)= ft ^n(b)的所有代数数t的集合有界Weil高.这是一个特殊的情况下,更一般的结果支持一个新的有界高度猜想的动力学。我们的结果适合算术动力学中不可能相交原理的一般设置。
We give new constructions of two classes of algebraic code families which are efficiently list decodable with small output list size from a fraction $1-R-ε$ of adversarial errors where $R$ is the rate of the code, for any desired positive constant $ε$. The alphabet size depends only $ε$ and is nearly-optimal. The first class of codes are obtained by folding algebraic-geometric codes using automorphisms of the underlying function field. The list decoding algorithm is based on a linear-algebraic approach, which pins down the candidate messages to a subspace with a nice "periodic" structure. The …