Siebert — Virtual Fundamental Classes, Global Normal Cones And Fulton’S Canonical Classes (2005)

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.