Homotopy principles for equivariant isomorphisms

dc.contributor.authorKutzschebauch, F.
dc.contributor.authorLárusson, F.
dc.contributor.authorSchwarz, G.
dc.date.issued2017
dc.descriptionArticle electronically published on May 5, 2017
dc.description.abstractLet G be a reductive complex Lie group acting holomorphically on Stein manifolds X and Y. Let pX : X → QX and pY : Y → QY be the quotient mappings. When is there an equivariant biholomorphism of X and Y ? A necessary condition is that the categorical quotients QX and QY are biholomorphic and that the biholomorphism ϕ sends the Luna strata of QX isomorphically onto the corresponding Luna strata of QY . Fix ϕ. We demonstrate two homotopy principles in this situation. The first result says that if there is a G-diffeomorphism Φ: X → Y , inducing ϕ, which is G-biholomorphic on the reduced fibres of the quotient mappings, then Φ is homotopic, through G-diffeomorphisms satisfying the same conditions, to a G-equivariant biholomorphism from X to Y . The second result roughly says that if we have a G-homeomorphism Φ: X → Y which induces a continuous family of Gequivariant biholomorphisms of the fibres pX −1(q) and pY −1(ϕ(q)) for q ∈ QX and if X satisfies an auxiliary property (which holds for most X), then Φ is homotopic, through G-homeomorphisms satisfying the same conditions, to a G-equivariant biholomorphism from X to Y . Our results improve upon those of our earlier paper [J. Reine Angew. Math. 706 (2015), 193–214] and use new ideas and techniques.
dc.description.statementofresponsibilityFrank Kutzschebauch, Finnur Lárusson, and Gerald W. Schwarz
dc.identifier.citationTransactions of the American Mathematical Society, 2017; 369(10):7251-7300
dc.identifier.doi10.1090/tran/6797
dc.identifier.issn0002-9947
dc.identifier.issn1088-6850
dc.identifier.urihttp://hdl.handle.net/2440/107496
dc.language.isoen
dc.publisherAmerican Mathematical Society
dc.relation.grant153120
dc.relation.granthttp://purl.org/au-research/grants/arc/DP120104110
dc.relation.granthttp://purl.org/au-research/grants/arc/DP150103442
dc.rights© 2017 American Mathematical Society
dc.source.urihttps://doi.org/10.1090/tran/6797
dc.subjectOka principle; geometric invariant theory; Stein manifold; complex Lie group; reductive group; categorical quotient; Luna stratification
dc.titleHomotopy principles for equivariant isomorphisms
dc.typeJournal article
pubs.publication-statusPublished

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