{"title":"Residually finite groups with uniformly almost flat quotients","authors":"David Guo, Matthew Tointon","doi":"10.1016/j.aim.2025.110495","DOIUrl":"10.1016/j.aim.2025.110495","url":null,"abstract":"<div><div>We show that if all the finite coset spaces of a polycyclic group have diameter bounded uniformly below by a polynomial in their size then the group is virtually nilpotent. We obtain the same conclusion for a finitely generated residually torsion-free nilpotent group under the weaker assumption that the finite quotient groups have diameter bounded uniformly below by a polynomial in their size. This extends work of Khukhro and Valette.</div></div>","PeriodicalId":50860,"journal":{"name":"Advances in Mathematics","volume":"480 ","pages":"Article 110495"},"PeriodicalIF":1.5,"publicationDate":"2025-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145026788","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Sharp asymptotic stability of Blasius profile in the steady Prandtl equation","authors":"Hao Jia , Zhen Lei , Cheng Yuan","doi":"10.1016/j.aim.2025.110533","DOIUrl":"10.1016/j.aim.2025.110533","url":null,"abstract":"<div><div>This work presents an asymptotic stability result concerning the self-similar Blasius profiles <span><math><mo>[</mo><mover><mrow><mi>u</mi></mrow><mrow><mo>¯</mo></mrow></mover><mo>,</mo><mover><mrow><mi>v</mi></mrow><mrow><mo>¯</mo></mrow></mover><mo>]</mo></math></span> of the stationary Prandtl boundary layer equation. Initially demonstrated by Serrin <span><span>[13]</span></span>, the profiles <span><math><mo>[</mo><mover><mrow><mi>u</mi></mrow><mrow><mo>¯</mo></mrow></mover><mo>,</mo><mover><mrow><mi>v</mi></mrow><mrow><mo>¯</mo></mrow></mover><mo>]</mo></math></span> were shown to act as a self-similar attractor of solutions <span><math><mo>[</mo><mi>u</mi><mo>,</mo><mi>v</mi><mo>]</mo></math></span> to the Prandtl equation through the use of von Mises transform and maximal principle techniques. Specifically, as <span><math><mi>x</mi><mo>→</mo><mo>∞</mo></math></span>, <span><math><msub><mrow><mo>‖</mo><mi>u</mi><mo>−</mo><mover><mrow><mi>u</mi></mrow><mrow><mo>¯</mo></mrow></mover><mo>‖</mo></mrow><mrow><msubsup><mrow><mi>L</mi></mrow><mrow><mi>y</mi></mrow><mrow><mo>∞</mo></mrow></msubsup></mrow></msub><mo>→</mo><mn>0</mn></math></span>. Iyer <span><span>[6]</span></span> employed refined energy methods to derive an explicit convergence rate for initial data close to Blasius. Wang and Zhang <span><span>[16]</span></span> utilized barrier function methods, removing smallness assumptions but imposing stronger asymptotic conditions on the initial data. It was suggested that the optimal convergence rate should be <span><math><msub><mrow><mo>‖</mo><mi>u</mi><mo>−</mo><mover><mrow><mi>u</mi></mrow><mrow><mo>¯</mo></mrow></mover><mo>‖</mo></mrow><mrow><msubsup><mrow><mi>L</mi></mrow><mrow><mi>y</mi></mrow><mrow><mo>∞</mo></mrow></msubsup></mrow></msub><mo>≲</mo><msup><mrow><mo>(</mo><mi>x</mi><mo>+</mo><mn>1</mn><mo>)</mo></mrow><mrow><mo>−</mo><mfrac><mrow><mn>1</mn></mrow><mrow><mn>2</mn></mrow></mfrac></mrow></msup></math></span>, treating the stationary Prandtl equation as a 1-D parabolic equation in the entire space.</div><div>In this study, we establish that <span><math><msub><mrow><mo>‖</mo><mi>u</mi><mo>−</mo><mover><mrow><mi>u</mi></mrow><mrow><mo>¯</mo></mrow></mover><mo>‖</mo></mrow><mrow><msubsup><mrow><mi>L</mi></mrow><mrow><mi>y</mi></mrow><mrow><mo>∞</mo></mrow></msubsup></mrow></msub><mo>≲</mo><msup><mrow><mo>(</mo><mi>x</mi><mo>+</mo><mn>1</mn><mo>)</mo></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></math></span>. Our proof relies on discovering nearly conserved low-frequency quantities and inherent degenerate structures at the boundary, which enhance the convergence rate through iteration techniques. Notably, the convergence rate we have demonstrated is optimal. We can find special solutions of Prandtl's equation such that the convergence between the solutions and the Blasius profile is exact, represented as <span><math><msup><mrow><mo>(</mo><mi>x</mi><mo>+</mo><mn>1</mn><mo>)</mo></mrow><mrow><mo>−</mo><mn>1</mn><","PeriodicalId":50860,"journal":{"name":"Advances in Mathematics","volume":"480 ","pages":"Article 110533"},"PeriodicalIF":1.5,"publicationDate":"2025-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145026789","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A monotonicity formula for minimal connections","authors":"Kotaro Kawai","doi":"10.1016/j.aim.2025.110513","DOIUrl":"10.1016/j.aim.2025.110513","url":null,"abstract":"<div><div>For Hermitian connections on a Hermitian complex line bundle over a Riemannian manifold <span><math><mo>(</mo><mi>X</mi><mo>,</mo><mi>g</mi><mo>)</mo></math></span>, we can define the “volume”, which can be considered to be the “mirror” of the standard volume for submanifolds. We call the critical points minimal connections.</div><div>In this paper, (1) we prove monotonicity formulas for minimal connections with respect to some versions of volume functionals under certain conditions on <span><math><mi>dim</mi><mo></mo><mi>X</mi></math></span> and the curvature of <em>g</em>. These formulas would be important in bubbling analysis. As a corollary, we obtain the vanishing theorem for minimal connections on the odd dimensional Euclidean space.</div><div>(2) We see that the formal “large radius limit” of the defining equation of minimal connections is that of Yang–Mills connections. Then the existence theorem of minimal connections is proved for a “sufficiently large” metric.</div><div>(3) We can consider deformed Donaldson–Thomas (dDT) connections on <span><math><msub><mrow><mi>G</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span>-manifolds as “mirrors” of calibrated (associative) submanifolds. We show that dDT connections are minimal connections, just as calibrated submanifolds are minimal submanifolds. By the argument specific to dDT connections, we obtain the stronger monotonicity formulas and vanishing theorem for dDT connections than in (1).</div></div>","PeriodicalId":50860,"journal":{"name":"Advances in Mathematics","volume":"480 ","pages":"Article 110513"},"PeriodicalIF":1.5,"publicationDate":"2025-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145018652","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Symplectic leaves in projective spaces of bundle extensions","authors":"Alexandru Chirvasitu","doi":"10.1016/j.aim.2025.110515","DOIUrl":"10.1016/j.aim.2025.110515","url":null,"abstract":"<div><div>Fix a stable degree-<em>n</em> rank-<em>k</em> bundle <span><math><mi>F</mi></math></span> on a complex elliptic curve for (coprime) <span><math><mn>1</mn><mo>≤</mo><mi>k</mi><mo><</mo><mi>n</mi><mo>≥</mo><mn>3</mn></math></span>. We identify the symplectic leaves of the Poisson structure introduced independently by Polishchuk and Feigin-Odesskii on <span><math><msup><mrow><mi>P</mi></mrow><mrow><mi>n</mi><mo>−</mo><mn>1</mn></mrow></msup><mo>≅</mo><mi>P</mi><msup><mrow><mi>Ext</mi></mrow><mrow><mn>1</mn></mrow></msup><mo>(</mo><mi>F</mi><mo>,</mo><mi>O</mi><mo>)</mo></math></span> as precisely the loci classifying extensions <span><math><mn>0</mn><mo>→</mo><mi>O</mi><mo>→</mo><mi>E</mi><mo>→</mo><mi>F</mi><mo>→</mo><mn>0</mn></math></span> with <span><math><mi>E</mi></math></span> fitting into a fixed isomorphism class, verifying a claim of Feigin-Odesskii. We also classify the bundles <span><math><mi>E</mi></math></span> which do fit into such extensions in geometric/combinatorial terms, involving their Harder-Narasimhan polygons introduced by Shatz.</div></div>","PeriodicalId":50860,"journal":{"name":"Advances in Mathematics","volume":"480 ","pages":"Article 110515"},"PeriodicalIF":1.5,"publicationDate":"2025-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145018654","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Webs for the quantum orthogonal group","authors":"Elijah Bodish , Haihan Wu","doi":"10.1016/j.aim.2025.110514","DOIUrl":"10.1016/j.aim.2025.110514","url":null,"abstract":"<div><div>We give a generators and relations presentation for the full monoidal subcategory of representations of the quantum orthogonal group generated by the quantum exterior powers of the defining representation.</div></div>","PeriodicalId":50860,"journal":{"name":"Advances in Mathematics","volume":"480 ","pages":"Article 110514"},"PeriodicalIF":1.5,"publicationDate":"2025-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145010092","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Dimension of diagonal self-affine measures with exponentially separated projections","authors":"Zhou Feng","doi":"10.1016/j.aim.2025.110511","DOIUrl":"10.1016/j.aim.2025.110511","url":null,"abstract":"<div><div>Let <em>μ</em> be a self-affine measure associated with a diagonal affine iterated function system (IFS) <span><math><mi>Φ</mi><mo>=</mo><msub><mrow><mo>{</mo><mo>(</mo><msub><mrow><mi>x</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>,</mo><mo>…</mo><mo>,</mo><msub><mrow><mi>x</mi></mrow><mrow><mi>d</mi></mrow></msub><mo>)</mo><mo>↦</mo><mo>(</mo><msub><mrow><mi>r</mi></mrow><mrow><mi>i</mi><mo>,</mo><mn>1</mn></mrow></msub><msub><mrow><mi>x</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>+</mo><msub><mrow><mi>t</mi></mrow><mrow><mi>i</mi><mo>,</mo><mn>1</mn></mrow></msub><mo>,</mo><mo>…</mo><mo>,</mo><msub><mrow><mi>r</mi></mrow><mrow><mi>i</mi><mo>,</mo><mi>d</mi></mrow></msub><msub><mrow><mi>x</mi></mrow><mrow><mi>d</mi></mrow></msub><mo>+</mo><msub><mrow><mi>t</mi></mrow><mrow><mi>i</mi><mo>,</mo><mi>d</mi></mrow></msub><mo>)</mo><mo>}</mo></mrow><mrow><mi>i</mi><mo>∈</mo><mi>Λ</mi></mrow></msub></math></span> on <span><math><msup><mrow><mi>R</mi></mrow><mrow><mi>d</mi></mrow></msup></math></span> and a probability vector <span><math><mi>p</mi><mo>=</mo><msub><mrow><mo>(</mo><msub><mrow><mi>p</mi></mrow><mrow><mi>i</mi></mrow></msub><mo>)</mo></mrow><mrow><mi>i</mi><mo>∈</mo><mi>Λ</mi></mrow></msub></math></span>. For <span><math><mn>1</mn><mo>≤</mo><mi>j</mi><mo>≤</mo><mi>d</mi></math></span>, denote the <em>j</em>-th Lyapunov exponent by <span><math><msub><mrow><mi>χ</mi></mrow><mrow><mi>j</mi></mrow></msub><mo>:</mo><mo>=</mo><msub><mrow><mo>∑</mo></mrow><mrow><mi>i</mi><mo>∈</mo><mi>Λ</mi></mrow></msub><mo>−</mo><msub><mrow><mi>p</mi></mrow><mrow><mi>i</mi></mrow></msub><mi>log</mi><mo></mo><mo>|</mo><msub><mrow><mi>r</mi></mrow><mrow><mi>i</mi><mo>,</mo><mi>j</mi></mrow></msub><mo>|</mo></math></span>, and define the IFS induced by Φ on the <em>j</em>-th coordinate as <span><math><msub><mrow><mi>Φ</mi></mrow><mrow><mi>j</mi></mrow></msub><mo>:</mo><mo>=</mo><msub><mrow><mo>{</mo><mi>x</mi><mo>↦</mo><msub><mrow><mi>r</mi></mrow><mrow><mi>i</mi><mo>,</mo><mi>j</mi></mrow></msub><mi>x</mi><mo>+</mo><msub><mrow><mi>t</mi></mrow><mrow><mi>i</mi><mo>,</mo><mi>j</mi></mrow></msub><mo>}</mo></mrow><mrow><mi>i</mi><mo>∈</mo><mi>Λ</mi></mrow></msub></math></span>. We prove that if <span><math><msub><mrow><mi>χ</mi></mrow><mrow><msub><mrow><mi>j</mi></mrow><mrow><mn>1</mn></mrow></msub></mrow></msub><mo>≠</mo><msub><mrow><mi>χ</mi></mrow><mrow><msub><mrow><mi>j</mi></mrow><mrow><mn>2</mn></mrow></msub></mrow></msub></math></span> for <span><math><mn>1</mn><mo>≤</mo><msub><mrow><mi>j</mi></mrow><mrow><mn>1</mn></mrow></msub><mo><</mo><msub><mrow><mi>j</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>≤</mo><mi>d</mi></math></span>, and <span><math><msub><mrow><mi>Φ</mi></mrow><mrow><mi>j</mi></mrow></msub></math></span> is exponentially separated for <span><math><mn>1</mn><mo>≤</mo><mi>j</mi><mo>≤</mo><mi>d</mi></math></span>, then the dimension of <em>μ</em> is the minimum of <em>d</em> and its Lyapunov dimension. This confirms a conjecture of ","PeriodicalId":50860,"journal":{"name":"Advances in Mathematics","volume":"480 ","pages":"Article 110511"},"PeriodicalIF":1.5,"publicationDate":"2025-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145010633","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Nakayama's lemma for Z-graded vertex algebras and its applications","authors":"Hao Wang , Wei Wang","doi":"10.1016/j.aim.2025.110503","DOIUrl":"10.1016/j.aim.2025.110503","url":null,"abstract":"<div><div>This is the first paper in a series of studies on <span><math><mi>Z</mi></math></span>-graded vertex algebras arising from Lie algebras with triangular decomposition (referred to as triangulated Lie algebras for simplicity). In this paper, we establish the Jacobson radical theory for <span><math><mi>Z</mi></math></span>-graded vertex algebras and prove Nakayama's lemma. As an application, we investigate a specific triangulated Lie algebra: <span><math><mi>g</mi><mo>=</mo><mi>C</mi><mi>f</mi><mo>⊕</mo><mi>C</mi><mi>h</mi><mo>⊕</mo><mi>C</mi><mi>e</mi></math></span> with Lie brackets <span><math><mo>[</mo><mi>h</mi><mo>,</mo><mi>e</mi><mo>]</mo><mo>=</mo><mn>2</mn><mi>e</mi><mo>,</mo><mspace></mspace><mo>[</mo><mi>h</mi><mo>,</mo><mi>f</mi><mo>]</mo><mo>=</mo><mo>−</mo><mn>2</mn><mi>f</mi><mo>,</mo><mspace></mspace><mo>[</mo><mi>e</mi><mo>,</mo><mi>f</mi><mo>]</mo><mo>=</mo><mn>0</mn></math></span>. Denote the <span><math><mi>Z</mi></math></span>-graded vertex algebra constructed from <span><math><mi>g</mi></math></span> by <span><math><msub><mrow><mi>V</mi></mrow><mrow><mi>g</mi></mrow></msub><mo>(</mo><mi>l</mi><mo>,</mo><mn>0</mn><mo>)</mo></math></span>. Using Nakayama's lemma, we classify all the irreducible admissible <span><math><msub><mrow><mi>V</mi></mrow><mrow><mi>g</mi></mrow></msub><mo>(</mo><mi>l</mi><mo>,</mo><mn>0</mn><mo>)</mo></math></span>-modules. Finally, we construct a class of indecomposable admissible <span><math><msub><mrow><mi>V</mi></mrow><mrow><mi>g</mi></mrow></msub><mo>(</mo><mi>l</mi><mo>,</mo><mn>0</mn><mo>)</mo></math></span>-modules.</div></div>","PeriodicalId":50860,"journal":{"name":"Advances in Mathematics","volume":"480 ","pages":"Article 110503"},"PeriodicalIF":1.5,"publicationDate":"2025-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144996258","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Frobenius structure and p-adic zeta values","authors":"Frits Beukers , Masha Vlasenko","doi":"10.1016/j.aim.2025.110512","DOIUrl":"10.1016/j.aim.2025.110512","url":null,"abstract":"<div><div>For differential operators of Calabi-Yau type, Candelas, De la Ossa and van Straten conjecture the appearance of <em>p</em>-adic zeta values in the matrix entries of their <em>p</em>-adic Frobenius structure expressed in the standard basis of solutions near a point of maximal unipotent local monodromy. We prove that this phenomenon holds for simplicial and hyperoctahedral families of Calabi-Yau hypersurfaces in <em>n</em> dimensions, in which case the limits of the Frobenius matrix entries are rational linear combinations of products of <span><math><msub><mrow><mi>ζ</mi></mrow><mrow><mi>p</mi></mrow></msub><mo>(</mo><mi>k</mi><mo>)</mo></math></span> with <span><math><mn>1</mn><mo><</mo><mi>k</mi><mo><</mo><mi>n</mi></math></span>.</div></div>","PeriodicalId":50860,"journal":{"name":"Advances in Mathematics","volume":"480 ","pages":"Article 110512"},"PeriodicalIF":1.5,"publicationDate":"2025-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144996257","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Equivariant cohomology of a complexity-one four-manifold is determined by combinatorial data","authors":"Tara S. Holm , Liat Kessler","doi":"10.1016/j.aim.2025.110497","DOIUrl":"10.1016/j.aim.2025.110497","url":null,"abstract":"<div><div>For Hamiltonian circle actions on compact, connected four-dimensional manifolds, we give a generators and relations description for the even part of the equivariant cohomology, as an algebra over the equivariant cohomology of a point. This description depends on combinatorial data encoded in the decorated graph of the manifold. We then give an explicit combinatorial description of all weak algebra isomorphisms. We use this description to prove that the even parts of the equivariant cohomology algebras are weakly isomorphic and the odd groups have the same ranks if and only if the labeled graphs obtained from the decorated graphs by forgetting the height and area labels are isomorphic.</div><div>As a consequence, we give an example of an isomorphism of equivariant cohomology algebras that cannot be induced by an equivariant diffeomorphism of manifolds preserving a compatible almost complex structure. We also provide a soft proof that there are finitely many maximal Hamiltonian circle actions on a fixed compact, connected, four-dimensional symplectic manifold.</div></div>","PeriodicalId":50860,"journal":{"name":"Advances in Mathematics","volume":"480 ","pages":"Article 110497"},"PeriodicalIF":1.5,"publicationDate":"2025-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144988158","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Homomorphisms between pure mapping class groups","authors":"Rodrigo De Pool","doi":"10.1016/j.aim.2025.110509","DOIUrl":"10.1016/j.aim.2025.110509","url":null,"abstract":"<div><div>Let <em>S</em> and <span><math><msup><mrow><mi>S</mi></mrow><mrow><mo>′</mo></mrow></msup></math></span> be orientable finite-type surfaces of genus <span><math><mi>g</mi><mo>≥</mo><mn>4</mn></math></span> and <span><math><msup><mrow><mi>g</mi></mrow><mrow><mo>′</mo></mrow></msup></math></span>, respectively. We prove that every multitwist-preserving map between pure mapping class groups <span><math><mi>PMap</mi><mo>(</mo><mi>S</mi><mo>)</mo><mo>→</mo><mi>PMap</mi><mo>(</mo><msup><mrow><mi>S</mi></mrow><mrow><mo>′</mo></mrow></msup><mo>)</mo></math></span> is induced by a multi-embedding. As an application, we classify all homomorphisms <span><math><mi>PMap</mi><mo>(</mo><mi>S</mi><mo>)</mo><mo>→</mo><mi>PMap</mi><mo>(</mo><msup><mrow><mi>S</mi></mrow><mrow><mo>′</mo></mrow></msup><mo>)</mo></math></span> for <span><math><mi>g</mi><mo>≥</mo><mn>4</mn></math></span> and <span><math><msup><mrow><mi>g</mi></mrow><mrow><mo>′</mo></mrow></msup><mo>≤</mo><mn>6</mn><mo>⋅</mo><msup><mrow><mn>2</mn></mrow><mrow><mi>g</mi><mo>−</mo><mn>4</mn></mrow></msup></math></span>.</div></div>","PeriodicalId":50860,"journal":{"name":"Advances in Mathematics","volume":"480 ","pages":"Article 110509"},"PeriodicalIF":1.5,"publicationDate":"2025-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144988157","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}