{"title":"On some congruences and exponential sums","authors":"Moubariz Z. Garaev , Igor E. Shparlinski","doi":"10.1016/j.ffa.2024.102451","DOIUrl":null,"url":null,"abstract":"<div><p>Let <span><math><mi>ε</mi><mo>></mo><mn>0</mn></math></span> be a fixed small constant, <span><math><msub><mrow><mi>F</mi></mrow><mrow><mi>p</mi></mrow></msub></math></span> be the finite field of <em>p</em> elements for prime <em>p</em>. We consider additive and multiplicative problems in <span><math><msub><mrow><mi>F</mi></mrow><mrow><mi>p</mi></mrow></msub></math></span> that involve intervals and arbitrary sets. Representative examples of our results are as follows. Let <span><math><mi>M</mi></math></span> be an arbitrary subset of <span><math><msub><mrow><mi>F</mi></mrow><mrow><mi>p</mi></mrow></msub></math></span>. If <span><math><mi>#</mi><mi>M</mi><mo>></mo><msup><mrow><mi>p</mi></mrow><mrow><mn>1</mn><mo>/</mo><mn>3</mn><mo>+</mo><mi>ε</mi></mrow></msup></math></span> and <span><math><mi>H</mi><mo>⩾</mo><msup><mrow><mi>p</mi></mrow><mrow><mn>2</mn><mo>/</mo><mn>3</mn></mrow></msup></math></span> or if <span><math><mi>#</mi><mi>M</mi><mo>></mo><msup><mrow><mi>p</mi></mrow><mrow><mn>3</mn><mo>/</mo><mn>5</mn><mo>+</mo><mi>ε</mi></mrow></msup></math></span> and <span><math><mi>H</mi><mo>⩾</mo><msup><mrow><mi>p</mi></mrow><mrow><mn>3</mn><mo>/</mo><mn>5</mn><mo>+</mo><mi>ε</mi></mrow></msup></math></span> then all, but <span><math><mi>O</mi><mo>(</mo><msup><mrow><mi>p</mi></mrow><mrow><mn>1</mn><mo>−</mo><mi>δ</mi></mrow></msup><mo>)</mo></math></span> elements of <span><math><msub><mrow><mi>F</mi></mrow><mrow><mi>p</mi></mrow></msub></math></span> can be represented in the form <em>hm</em> with <span><math><mi>h</mi><mo>∈</mo><mo>[</mo><mn>1</mn><mo>,</mo><mi>H</mi><mo>]</mo></math></span> and <span><math><mi>m</mi><mo>∈</mo><mi>M</mi></math></span>, where <span><math><mi>δ</mi><mo>></mo><mn>0</mn></math></span> depends only on <em>ε</em>. Furthermore, let <span><math><mi>X</mi></math></span> be an arbitrary interval of length <em>H</em> and <em>s</em> be a fixed positive integer. If<span><span><span><math><mi>H</mi><mo>></mo><msup><mrow><mi>p</mi></mrow><mrow><mn>17</mn><mo>/</mo><mn>35</mn><mo>+</mo><mi>ε</mi></mrow></msup><mo>,</mo><mspace></mspace><mi>#</mi><mi>M</mi><mo>></mo><msup><mrow><mi>p</mi></mrow><mrow><mn>17</mn><mo>/</mo><mn>35</mn><mo>+</mo><mi>ε</mi></mrow></msup><mo>,</mo></math></span></span></span> then the number <span><math><msub><mrow><mi>T</mi></mrow><mrow><mn>6</mn></mrow></msub><mo>(</mo><mi>λ</mi><mo>)</mo></math></span> of solutions to the congruence<span><span><span><math><mfrac><mrow><msub><mrow><mi>m</mi></mrow><mrow><mn>1</mn></mrow></msub></mrow><mrow><msubsup><mrow><mi>x</mi></mrow><mrow><mn>1</mn></mrow><mrow><mi>s</mi></mrow></msubsup></mrow></mfrac><mo>+</mo><mfrac><mrow><msub><mrow><mi>m</mi></mrow><mrow><mn>2</mn></mrow></msub></mrow><mrow><msubsup><mrow><mi>x</mi></mrow><mrow><mn>2</mn></mrow><mrow><mi>s</mi></mrow></msubsup></mrow></mfrac><mo>+</mo><mfrac><mrow><msub><mrow><mi>m</mi></mrow><mrow><mn>3</mn></mrow></msub></mrow><mrow><msubsup><mrow><mi>x</mi></mrow><mrow><mn>3</mn></mrow><mrow><mi>s</mi></mrow></msubsup></mrow></mfrac><mo>+</mo><mfrac><mrow><msub><mrow><mi>m</mi></mrow><mrow><mn>4</mn></mrow></msub></mrow><mrow><msubsup><mrow><mi>x</mi></mrow><mrow><mn>4</mn></mrow><mrow><mi>s</mi></mrow></msubsup></mrow></mfrac><mo>+</mo><mfrac><mrow><msub><mrow><mi>m</mi></mrow><mrow><mn>5</mn></mrow></msub></mrow><mrow><msubsup><mrow><mi>x</mi></mrow><mrow><mn>5</mn></mrow><mrow><mi>s</mi></mrow></msubsup></mrow></mfrac><mo>+</mo><mfrac><mrow><msub><mrow><mi>m</mi></mrow><mrow><mn>6</mn></mrow></msub></mrow><mrow><msubsup><mrow><mi>x</mi></mrow><mrow><mn>6</mn></mrow><mrow><mi>s</mi></mrow></msubsup></mrow></mfrac><mo>≡</mo><mi>λ</mi><mspace></mspace><mrow><mi>mod</mi></mrow><mspace></mspace><mi>p</mi><mo>,</mo><msub><mrow><mi>m</mi></mrow><mrow><mi>i</mi></mrow></msub><mo>∈</mo><mi>M</mi><mo>,</mo><mspace></mspace><msub><mrow><mi>x</mi></mrow><mrow><mi>i</mi></mrow></msub><mo>∈</mo><mi>X</mi><mo>,</mo><mspace></mspace><mi>i</mi><mo>=</mo><mn>1</mn><mo>,</mo><mo>…</mo><mo>,</mo><mn>6</mn><mo>,</mo></math></span></span></span> satisfies<span><span><span><math><msub><mrow><mi>T</mi></mrow><mrow><mn>6</mn></mrow></msub><mo>(</mo><mi>λ</mi><mo>)</mo><mo>=</mo><mfrac><mrow><msup><mrow><mi>H</mi></mrow><mrow><mn>6</mn></mrow></msup><msup><mrow><mo>(</mo><mi>#</mi><mi>M</mi><mo>)</mo></mrow><mrow><mn>6</mn></mrow></msup></mrow><mrow><mi>p</mi></mrow></mfrac><mrow><mo>(</mo><mn>1</mn><mo>+</mo><mi>O</mi><mo>(</mo><msup><mrow><mi>p</mi></mrow><mrow><mo>−</mo><mi>δ</mi></mrow></msup><mo>)</mo><mo>)</mo></mrow><mo>.</mo></math></span></span></span></p></div>","PeriodicalId":50446,"journal":{"name":"Finite Fields and Their Applications","volume":null,"pages":null},"PeriodicalIF":1.2000,"publicationDate":"2024-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S107157972400090X/pdfft?md5=73d751bad88083ca796c715f3b4d9bad&pid=1-s2.0-S107157972400090X-main.pdf","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Finite Fields and Their Applications","FirstCategoryId":"100","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S107157972400090X","RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"MATHEMATICS","Score":null,"Total":0}
引用次数: 0
Abstract
Let be a fixed small constant, be the finite field of p elements for prime p. We consider additive and multiplicative problems in that involve intervals and arbitrary sets. Representative examples of our results are as follows. Let be an arbitrary subset of . If and or if and then all, but elements of can be represented in the form hm with and , where depends only on ε. Furthermore, let be an arbitrary interval of length H and s be a fixed positive integer. If then the number of solutions to the congruence satisfies
期刊介绍:
Finite Fields and Their Applications is a peer-reviewed technical journal publishing papers in finite field theory as well as in applications of finite fields. As a result of applications in a wide variety of areas, finite fields are increasingly important in several areas of mathematics, including linear and abstract algebra, number theory and algebraic geometry, as well as in computer science, statistics, information theory, and engineering.
For cohesion, and because so many applications rely on various theoretical properties of finite fields, it is essential that there be a core of high-quality papers on theoretical aspects. In addition, since much of the vitality of the area comes from computational problems, the journal publishes papers on computational aspects of finite fields as well as on algorithms and complexity of finite field-related methods.
The journal also publishes papers in various applications including, but not limited to, algebraic coding theory, cryptology, combinatorial design theory, pseudorandom number generation, and linear recurring sequences. There are other areas of application to be included, but the important point is that finite fields play a nontrivial role in the theory, application, or algorithm.