Theory of multi-fans

dc.creatorHattori, Akio
dc.creatorMasuda, Mikiya
dc.date2001-06-27
dc.date2003-12-10
dc.date.accessioned2026-07-07T04:42:20Z
dc.date.available2026-07-07T04:42:20Z
dc.descriptionWe introduce the notion of a multi-fan. It is a generalization of that of a fan in the theory of toric variety in algebraic geometry. Roughly speaking a toric variety is an algebraic variety with an action of algebraic torus of the same dimension as that of the variety, and a fan is a combinatorial object associated with the toric variety. Algebro-geometric properties of the toric variety can be described in terms of the associated fan. We develop a combinatorial theory of multi-fans and define ``topological invariants'' of a multi-fan. A smooth manifold with an action of a compact torus of half the dimension of the manifold and with some orientation data is called a torus manifold. We associate a multi-fan with a torus manifold, and apply the combinatorial theory to describe topological invariants of the torus manifold. A similar theory is also given for torus orbifolds. As a related subject a generalization of the Ehrhart polynomial concerning the number of lattice points in a convex polytope is discussed.
dc.identifierhttps://arxiv.org/abs/math/0106229
dc.identifierhttp://arxiv.org/abs/math/0106229
dc.identifierOsaka J. Math. 40 (2003), 1-68
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/61737
dc.subjectSymplectic Geometry
dc.subjectAlgebraic Topology
dc.titleTheory of multi-fans
dc.typetext

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