Cancellation for Surfaces Revisited

• Autore: Flenner H
• Pubblicazione: Providence : , : American Mathematical Society, , 2022; ©2022
• Edizione: 1st ed.
• Descrizione fisica: 1 online resource (124 pages)
• Disciplina: 516.3/52; 516.352
• Soggetto topico: Surfaces, Algebraic; Cancellation theory (Group theory); Moduli theory; Algebraic geometry -- Affine geometry -- Affine spaces (automorphisms, embeddings, exotic structures, cancellation problem); Algebraic geometry -- Families, fibrations -- Fine and coarse moduli spaces
• Classificazione: 14R1014D22
• Altri autori: KalimanS ZaidenbergM
• Nota di contenuto: Cover -- Title page -- Introduction -- Chapter 1. Generalities -- 1.1. Cancellation and the Makar-Limanov invariant -- 1.2. Non-cancellation and Gizatullin surfaces -- 1.3. The Danielewski-Fieseler construction -- 1.4. Affine modifications -- Chapter 2. ¹-fibered surfaces via affine modifications -- 2.1. Covering trick and GDF surfaces -- 2.2. Pseudominimal completion and extended divisor -- 2.3. Blowup construction -- 2.4. GDF surfaces via affine modifications -- Chapter 3. Vector fields and natural coordinates -- 3.1. Locally nilpotent vertical vector fields -- 3.2. Standard affine charts -- 3.3. Natural coordinates -- 3.4. Special _{ }-quasi-invariants -- 3.5. Examples of GDF surfaces of Danielewski type -- Chapter 4. Relative flexibility -- 4.1. Definitions and the main theorem -- 4.2. Transitive group actions on Veronese cones -- 4.3. Relatively transitive group actions on cylinders -- 4.4. A relative Abhyankar-Moh-Suzuki Theorem -- Chapter 5. Rigidity of cylinders upon deformation of surfaces -- 5.1. Equivariant Asanuma modification -- 5.2. Rigidity of cylinders under deformations of GDF surfaces -- 5.3. Rigidity of cylinders under deformations of ¹-fibered surfaces -- 5.4. Rigidity of line bundles over affine surfaces -- Chapter 6. Basic examples of Zariski factors -- 6.1. Line bundles over affine curves -- 6.2. Parabolic _{ }-surfaces: an overview -- 6.3. Parabolic _{ }-surfaces as Zariski factors -- Chapter 7. Zariski 1-factors -- 7.1. Stretching and rigidity of cylinders -- 7.2. Non-cancellation for GDF surfaces -- 7.3. Extended graphs of Gizatullin surfaces -- 7.4. Zariski 1-factors and affine ¹-fibered surfaces -- Chapter 8. Classical examples -- Chapter 9. GDF surfaces with isomorphic cylinders -- 9.1. Preliminaries -- 9.2. Classification of GDF cylinders up to -isomorphism -- 9.3. GDF surfaces whose fiber trees are bushes. ; 9.4. Spring bushes versus bushes -- 9.5. Cylinders over Danielewski-Fieseler surfaces -- 9.6. Proof of the main theorem -- Chapter 10. On moduli spaces of GDF surfaces -- 10.1. Coarse moduli spaces of GDF surfaces -- 10.2. The automorphism group of a GDF surface -- 10.3. Configuration spaces and configuration invariants -- 10.4. Versal deformation families of trivializing sequences -- 10.5. Proof of Theorem 10.1.3 -- Acknowledgments -- Bibliography -- Back Cover.
• Sommario/riassunto: "The celebrated Zariski Cancellation Problem asks as to when the existence of an isomorphism X An X An for (affine) algebraic varieties X and X implies that X X. In this paper we provide a criterion for cancellation by the affine line (that is, n 1) in the case where X is a normal affine surface admitting an A1-fibration X B with no multiple fiber over a smooth affine curve B. For two such surfaces X B and X B we give a criterion as to when the cylinders X A1 and X A1 are isomorphic over B. The latter criterion is expressed in terms of linear equivalence of certain divisors on the Danielewski-Fieseler quotient of X over B. It occurs that for a smooth A1-fibered surface X B the cancellation by the affine line holds if and only if X B is a line bundle, and, for a normal such X, if and only if X B is a cyclic quotient of a line bundle (an orbifold line bundle). If X does not admit any A1-fibration over an affine base then the cancellation by the affine line is known to hold for X by a result of Bandman and Makar-Limanov. If the cancellation does not hold then X deforms in a non-isotrivial family of A1-fibered surfaces B with cylinders A1 isomorphic over B. We construct such versal deformation families and their coarse moduli spaces provided B does not admit nonconstant invertible functions. Each of these coarse moduli spaces has infinite number of irreducible components of growing dimensions; each component is an affine variety with quotient singularities. Finally, we analyze from our viewpoint the examples of non-cancellation constructed by Danielewski, tom Dieck, Wilkens, Masuda and Miyanishi, e.a"--
• Titolo autorizzato: Cancellation for Surfaces Revisited
• ISBN: 9781470471712; 147047171X
• Formato: Materiale a stampa
• Livello bibliografico: Monografia
• Lingua di pubblicazione: Inglese
• Record Nr.: 9910973246903321
• Lo trovi qui: Univ. Federico II
• Serie: Memoirs of the American Mathematical Society