Resumen de Orbifold thechniques in degeneration formulas

Dan Abramovich, Barbara Fantechi

• We give a new approach for relative and degenerate Gromov-Witten invariants, inspired by that ofJun Li but replacing predeformable maps by transversal maps to a twisted target. The main advantage is a significant simplification in the definition of the obstruction theory. We reprove in our language the degeneration formula, extending it to the orbifold case