20,270 research outputs found

    A note on Diophantine systems involving three symmetric polynomials

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    Let Xˉn=(x1,,xn)\bar{X}_{n}=(x_{1},\ldots,x_{n}) and σi(Xˉn)=xk1xki\sigma_{i}(\bar{X}_{n})=\sum x_{k_{1}}\ldots x_{k_{i}} be ii-th elementary symmetric polynomial. In this note we prove that there are infinitely many triples of integers a,b,ca, b, c such that for each 1in1\leq i\leq n the system of Diophantine equations \begin{equation*} \sigma_{i}(\bar{X}_{2n})=a, \quad \sigma_{2n-i}(\bar{X}_{2n})=b, \quad \sigma_{2n}(\bar{X}_{2n})=c \end{equation*} has infinitely many rational solutions. This result extend the recent results of Zhang and Cai, and the author. Moreover, we also consider some Diophantine systems involving sums of powers. In particular, we prove that for each kk there are at least kk nn-tuples of integers with the same sum of ii-th powers for i=1,2,3i=1,2,3. Similar result is proved for i=1,2,4i=1,2,4 and i=1,1,2i=-1,1,2.Comment: to appear in J. Number Theor

    kk-partial permutations and the center of the wreath product SkSn\mathcal{S}_k\wr \mathcal{S}_n algebra

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    We generalize the concept of partial permutations of Ivanov and Kerov and introduce kk-partial permutations. This allows us to show that the structure coefficients of the center of the wreath product SkSn\mathcal{S}_k\wr \mathcal{S}_n algebra are polynomials in nn with non-negative integer coefficients. We use a universal algebra Ik\mathcal{I}_\infty^k which projects on the center Z(C[SkSn])Z(\mathbb{C}[\mathcal{S}_k\wr \mathcal{S}_n]) for each n.n. We show that Ik\mathcal{I}_\infty^k is isomorphic to the algebra of shifted symmetric functions on many alphabets

    Explicit Formulae for LL-values in Positive Characteristic

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    We focus on the generating series for the rational special values of Pellarin's LL-series in 1s2(q1)1 \leq s \leq 2(q-1) indeterminates, and using interpolation polynomials we prove a closed form formula relating this generating series to the Carlitz exponential, the Anderson-Thakur function, and the Anderson generating functions for the Carlitz module. We draw several corollaries, including explicit formulae and recursive relations for Pellarin's LL-series in the same range of ss, and divisibility results on the numerators of the Bernoulli-Carlitz numbers by monic irreducibles of degrees one and two.Comment: Some helpful clarifications in the introduction. Final edit, as appears online in Math.

    Permutation combinatorics of worldsheet moduli space

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    52 pages, 21 figures52 pages, 21 figures; minor corrections, "On the" dropped from title, matches published version52 pages, 21 figures; minor corrections, "On the" dropped from title, matches published versio

    Every sufficiently large even number is the sum of two primes

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    The binary Goldbach conjecture asserts that every even integer greater than 44 is the sum of two primes. In this paper, we prove that there exists an integer KαK_\alpha such that every even integer x>pk2x > p_k^2 can be expressed as the sum of two primes, where pkp_k is the kkth prime number and k>Kαk > K_\alpha. To prove this statement, we begin by introducing a type of double sieve of Eratosthenes as follows. Given a positive even integer x>4x > 4, we sift from [1,x][1, x] all those elements that are congruents to 00 modulo pp or congruents to xx modulo pp, where pp is a prime less than x\sqrt{x}. Therefore, any integer in the interval [x,x][\sqrt{x}, x] that remains unsifted is a prime qq for which either xq=1x-q = 1 or xqx-q is also a prime. Then, we introduce a new way of formulating a sieve, which we call the sequence of kk-tuples of remainders. By means of this tool, we prove that there exists an integer Kα>5K_\alpha > 5 such that pk/2p_k / 2 is a lower bound for the sifting function of this sieve, for every even number xx that satisfies pk2<x<pk+12p_k^2 < x < p_{k+1}^2, where k>Kαk > K_\alpha, which implies that x>pk2  (k>Kα)x > p_k^2 \; (k > K_\alpha) can be expressed as the sum of two primes.Comment: 32 pages. The manuscript was edited for proper English language by one editor at American Journal Experts (Certificate Verification Key: C0C3-5251-4504-E14D-BE84). However, afterwards some changes have been made in sections 1, 6, 7 and
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