2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/112779We give a direct proof of a cancellation formula raised in [7] on the level of differential forms. We also obtain more cancellation formulas for even dimensional Riemannian manifolds with a complex line bundle involved. Relations among these cancellation formulas are discussed.To Appear on the Transactions of AMSDifferential GeometryAlgebraic TopologyPrimary 53C20, 57R20; Secondary 53C80, 11Z05text