Nonstabilized Nielsen coincidence invariants and Hopf--Ganea homomorphisms

dc.creatorKoschorke, Ulrich
dc.date2006-06-01
dc.date2009-03-01
dc.date.accessioned2026-07-07T12:47:21Z
dc.date.available2026-07-07T12:47:21Z
dc.descriptionIn classical fixed point and coincidence theory the notion of Nielsen numbers has proved to be extremely fruitful. We extend it to pairs (f_1,f_2) of maps between manifolds of arbitrary dimensions, using nonstabilized normal bordism theory as our main tool. This leads to estimates of the minimum numbers MCC(f_1,f_2) (and MC(f_1,f_2), respectively) of path components (and of points, resp.) in the coincidence sets of those pairs of maps which are homotopic to (f_1,f_2). Furthermore, we deduce finiteness conditions for MC(f_1,f_2). As an application we compute both minimum numbers explicitly in various concrete geometric sample situations. The Nielsen decomposition of a coincidence set is induced by the decomposition of a certain path space E(f_1,f_2) into path components. Its higher dimensional topology captures further crucial geometric coincidence data. In the setting of homotopy groups the resulting invariants are closely related to certain Hopf--Ganea homomorphisms which turn out to yield finiteness obstructions for MC.
dc.descriptionThis is the version published by Geometry & Topology on 24 May 2006
dc.identifierhttps://arxiv.org/abs/math/0606025
dc.identifierhttp://arxiv.org/abs/math/0606025
dc.identifierGeom. Topol. 10 (2006) 619-666
dc.identifierdoi:10.2140/gt.2006.10.619
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/221693
dc.subjectAlgebraic Topology
dc.subjectGeometric Topology
dc.subject55M20, 55Q25, 55S35, 57R90, 55N22, 55P35, 55Q40
dc.titleNonstabilized Nielsen coincidence invariants and Hopf--Ganea homomorphisms
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