2005/09/04 by Bernd Siebert
Mathematics · #math.AG #msc:14N35
published as Frobenius manifolds, pp. 341--358, Aspects Math., E36, Vieweg 2004 · This version differs from the published text in correcting statements on mere dependence of cohomology rather than homotopy. These were based on a flawed splitting statement, as pointed out by Charles Cadman. Moreover, the proof of Proposition 2.11 required more attention. 16 pages
This paper, first written in 1997, aims at a simplified and more elementary construction of algebraic-geometric virtual fundamental classes as defined by Li/Tian and Behrend/Fantechi. We replace the use of Artin stacks in the latter approach by a yoga of cone bundles of possible independent interest. We also observe a formula for virtual fundamental classes involving only the total Chern class of the index bundle and Fulton's canonical class of the moduli space.