Rational obstruction theory and rational homotopy sets

dc.creatorArkowitz, M.
dc.creatorLupton, G.
dc.date2000-10-12
dc.date.accessioned2026-07-07T04:37:59Z
dc.date.available2026-07-07T04:37:59Z
dc.descriptionWe develop an obstruction theory for homotopy of homomorphisms f,g : M -> N between minimal differential graded algebras. We assume that M = Lambda V has an obstruction decomposition given by V = V_0 oplus V_1 and that f and g are homotopic on Lambda V_0. An obstruction is then obtained as a vector space homomorphism V_1 -> H^*(N). We investigate the relationship between the condition that f and g are homotopic and the condition that the obstruction is zero. The obstruction theory is then applied to study the set of homotopy classes [M, N]. This enables us to give a fairly complete answer to a conjecture of Copeland-Shar on the size of the homotopy set [A,B] when A and B are rational spaces. In addition, we give examples of minimal algebras (and hence of rational spaces) that have few homotopy classes of self-maps.
dc.descriptionTo appear, Math. Zeit
dc.identifierhttps://arxiv.org/abs/math/0010126
dc.identifierhttp://arxiv.org/abs/math/0010126
dc.identifierMath. Zeit., Vol. 235 (2000), 525--539.
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/60114
dc.subjectAlgebraic Topology
dc.subject55P62, 55Q05, 55S35 (Primary); 55P10 (Secondary)
dc.titleRational obstruction theory and rational homotopy sets
dc.typetext

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