{"title":"Transcendental Brauer-Manin obstructions on singular K3 surfaces.","authors":"Mohamed Alaa Tawfik, Rachel Newton","doi":"10.1007/s40993-024-00580-z","DOIUrl":"10.1007/s40993-024-00580-z","url":null,"abstract":"<p><p>Let <i>E</i> and <math><msup><mi>E</mi> <mo>'</mo></msup> </math> be elliptic curves over <math><mi>Q</mi></math> with complex multiplication by the ring of integers of an imaginary quadratic field <i>K</i> and let <math><mrow><mi>Y</mi> <mo>=</mo> <mrow><mspace></mspace> <mtext>Kum</mtext> <mspace></mspace></mrow> <mo>(</mo> <mi>E</mi> <mo>×</mo> <msup><mi>E</mi> <mo>'</mo></msup> <mo>)</mo></mrow> </math> be the minimal desingularisation of the quotient of <math><mrow><mi>E</mi> <mo>×</mo> <msup><mi>E</mi> <mo>'</mo></msup> </mrow> </math> by the action of <math><mrow><mo>-</mo> <mn>1</mn></mrow> </math> . We study the Brauer groups of such surfaces <i>Y</i> and use them to furnish new examples of transcendental Brauer-Manin obstructions to weak approximation.</p>","PeriodicalId":43826,"journal":{"name":"Research in Number Theory","volume":"11 1","pages":"16"},"PeriodicalIF":0.6,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11655618/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142878096","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Traces of partition Eisenstein series and almost holomorphic modular forms.","authors":"Kathrin Bringmann, Badri Vishal Pandey","doi":"10.1007/s40993-025-00615-z","DOIUrl":"10.1007/s40993-025-00615-z","url":null,"abstract":"<p><p>Recently, Amdeberhan, Griffin, Ono, and Singh started the study of \"traces of partition Eisenstein series\" and used it to give explicit formulas for many interesting functions. In this note we determine the precise spaces in which they lie, find modular completions, and show how they are related via operators.</p>","PeriodicalId":43826,"journal":{"name":"Research in Number Theory","volume":"11 2","pages":"49"},"PeriodicalIF":0.6,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12018508/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143989987","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Constructing families of 3-Selmer companions.","authors":"Harry Spencer","doi":"10.1007/s40993-025-00647-5","DOIUrl":"https://doi.org/10.1007/s40993-025-00647-5","url":null,"abstract":"<p><p>Mazur and Rubin introduced the notion of <i>n</i>-Selmer companion elliptic curves and gave several examples of pairs of non-isogenous Selmer companions. We construct several pairs of families of elliptic curves, each parameterised by <math><mrow><mi>t</mi> <mo>∈</mo> <mi>Z</mi></mrow> </math> , such that the two curves in a pair corresponding to a given <i>t</i> are non-isogenous 3-Selmer companions, possibly provided that <i>t</i> satisfies a simple congruence condition.</p>","PeriodicalId":43826,"journal":{"name":"Research in Number Theory","volume":"11 3","pages":"67"},"PeriodicalIF":0.6,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12227473/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144576602","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Daniel Barrera Salazar, Andrew Graham, Chris Williams
{"title":"<ArticleTitle xmlns:ns0=\"http://www.w3.org/1998/Math/MathML\">On <i>p</i>-refined Friedberg-Jacquet integrals and the classical symplectic locus in the <ns0:math> <ns0:msub><ns0:mrow><ns0:mspace /> <ns0:mtext>GL</ns0:mtext> <ns0:mspace /></ns0:mrow> <ns0:mrow><ns0:mn>2</ns0:mn> <ns0:mi>n</ns0:mi></ns0:mrow> </ns0:msub> </ns0:math> eigenvariety.","authors":"Daniel Barrera Salazar, Andrew Graham, Chris Williams","doi":"10.1007/s40993-025-00631-z","DOIUrl":"https://doi.org/10.1007/s40993-025-00631-z","url":null,"abstract":"<p><p>Friedberg-Jacquet proved that if <math><mi>π</mi></math> is a cuspidal automorphic representation of <math> <mrow><msub><mtext>GL</mtext> <mrow><mn>2</mn> <mi>n</mi></mrow> </msub> <mrow><mo>(</mo> <mi>A</mi> <mo>)</mo></mrow> </mrow> </math> , then <math><mi>π</mi></math> is a functorial transfer from <math><msub><mtext>GSpin</mtext> <mrow><mn>2</mn> <mi>n</mi> <mo>+</mo> <mn>1</mn></mrow> </msub> </math> if and only if a global zeta integral <math><msub><mi>Z</mi> <mi>H</mi></msub> </math> over <math><mrow><mi>H</mi> <mo>=</mo> <msub><mtext>GL</mtext> <mi>n</mi></msub> <mo>×</mo> <msub><mtext>GL</mtext> <mi>n</mi></msub> </mrow> </math> is non-vanishing on <math><mi>π</mi></math> . We conjecture a <i>p</i>-refined analogue: that any <i>P</i>-parahoric <i>p</i>-refinement <math> <msup><mover><mi>π</mi> <mo>~</mo></mover> <mi>P</mi></msup> </math> is a functorial transfer from <math><msub><mtext>GSpin</mtext> <mrow><mn>2</mn> <mi>n</mi> <mo>+</mo> <mn>1</mn></mrow> </msub> </math> if and only if a <i>P</i>-twisted version of <math><msub><mi>Z</mi> <mi>H</mi></msub> </math> is non-vanishing on the <math> <msup><mover><mi>π</mi> <mo>~</mo></mover> <mi>P</mi></msup> </math> -eigenspace in <math><mi>π</mi></math> . This twisted <math><msub><mi>Z</mi> <mi>H</mi></msub> </math> appears in all constructions of <i>p</i>-adic <i>L</i>-functions via Shalika models. We connect our conjecture to the study of classical symplectic families in the <math><msub><mtext>GL</mtext> <mrow><mn>2</mn> <mi>n</mi></mrow> </msub> </math> eigenvariety, and-by proving upper bounds on the dimensions of such families-obtain various results towards the conjecture.</p>","PeriodicalId":43826,"journal":{"name":"Research in Number Theory","volume":"11 2","pages":"51"},"PeriodicalIF":0.6,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12031854/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144028936","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}