Chow groups of the moduli spaces of weighted pointed stable curves of genus zero

The moduli space (M) over bar (A) of weighted pointed stable curves of genus zero is stratified according to the degeneration types of such curves. We show that the homology groups of (M) over bar (A) are generated by the strata of (M) over bar (A) and give all additive relations between them. We also observe that the Chow groups A(i)(M) over bar (A) and the homology groups H(2i)(M) over bar (A) are isomorphic. This generalizes Kontsevich-Manin's and Losev-Manin's theorems to arbitrary weight data A. (C) 2009 Elsevier Inc. All rights reserved.