We give a new proof of a result of DiPippo and Wan for counting points of bounded height on projective spaces over global function fields. The new proof adapts the geometry of numbers arguments used by Schanuel in the number field case.
We give a new proof of a result of DiPippo and Wan for counting points of bounded height on projective spaces over global function fields. The new proof adapts the geometry of numbers arguments used by Schanuel in the number field case.
This paper corrects an error in the proof of Theorem 1.4 (3) of our earlier paper, Further Improvements to the Chevalley-Warning Theorems. The error originally appeared in Heath-Brown's paper, On Chevalley-Warning Theorems, which invalidates the proof of Theorem 2 (iii) in that paper. In this paper, we use a new method to give a correct proof of Theorem 1.4 (3). The correction in this paper also fixes the proof of Theorem 2 (iii) in Heath-Brown's paper. The proof in this paper provides slightly stronger estimates for some of the inequalities that were used in Further Improvements to the Chevalley-Warning Theorems.
The arithmetic crosscorrelation of binary m-sequences with coprime periods and () is determined. The result shows that the absolute value of arithmetic crosscorrelation of such binary m-sequences is not greater than .
Starting with the multiplication of elements in which is consistent with that over , where q is a prime power, via some identification of the two environments, we investigate the c-differential uniformity for bivariate functions . By carefully choosing the functions and , we present several constructions of bivariate functions with low c-differential uniformity, in particular, many PcN and APcN functions can be produced from our constructions.
In this paper, we study constacyclic codes of length over a finite field of characteristics p, where is an odd prime number and s a positive integer. The previous methods in the literature that were used to compute the Hamming distances of repeated-root constacyclic codes of lengths with cannot be applied to completely determine the Hamming distances of those with . This is due to the high computational complexity involved and the large number of unexpected intermediate results that arise during the computation. To overcome this challenge, we propose a computer-assisted method for determining the Hamming distances of simple-root constacyclic codes of length 7, and then utilize it to derive the Hamming distances of the repeated-root constacyclic codes of length . Our method is not only straightforward to implement but also efficient, making it applicable to these codes with larger values of n as well. In addition, all self-orthogonal, dual-containing, self-dual, MDS and AMDS codes among them will also be characterized.
A subspace of is called a cyclically covering subspace if for every vector of , operating a certain number of cyclic shifts on it, the resulting vector lies in the subspace. In this paper, we study the problem of under what conditions is itself the only covering subspace of , symbolically, , which is an open problem posed in Cameron et al. (2019) [3] and Aaronson et al. (2021) [1]. We apply the primitive idempotents of the cyclic group algebra to attack this problem; when q is relatively prime to n, we obtain a necessary and sufficient condition under which , which completely answers the problem in this case. Our main result reveals that the problem can be fully reduced to that of determining the values of the trace function over finite fields. As consequences, we explicitly determine several infinitely families of which satisfy .
The a-number is an invariant of the isomorphism class of the p-torsion group scheme. We use the Cartier operator on to find a closed formula for the a-number of the form where over the finite field . The application of the computed a-number in coding theory is illustrated by the relationship between the algebraic properties of the curve and the parameters of codes that are supported by it.
We consider information-theoretical private information retrieval (PIR) from a coded database with colluding servers. We target, for the first time, locally repairable storage codes (LRCs). We consider any number of local groups g, locality r, local distance δ and dimension k. Our main contribution is a PIR scheme for maximally recoverable (MR) LRCs based on linearized Reed–Solomon codes, which achieve the smallest field sizes among MR-LRCs for many parameter regimes. In our scheme, nodes are identified with codeword symbols and servers are identified with local groups of nodes. Only locally non-redundant information is downloaded from each server, that is, only r nodes (out of ) are downloaded per server. The PIR scheme achieves the (download) rate , where is the length of the MDS code obtained after removing the local parities, and for any t colluding servers such that . For an unbounded number of stored files, the obtained rate is strictly larger than those of known PIR schemes that work for any MDS code. Finally, the obtained PIR scheme can also be adapted when communication between the user and each server is performed via linear network coding, achieving the same rate as previous PIR schemes for this scenario but with polynomial finite field sizes, instead of exponential. Our rates are equal to those of PIR schemes for Reed–Solomon codes, but Reed–Solomon codes are incompatible with the MR-LRC property or linear network coding, thus our PIR scheme is less restrictive in its applications.
For a finite field with fixed q and r sufficiently large, we prove the existence of a primitive element outside of a set of r many affine hyperplanes for and . This complements earlier results by Fernandes and Reis for . For the analogous result can be derived from a very recent bound on character sums of Iyer and Shparlinski. For the set consists only of a single element, and such a result is thus not possible.