  We give an approach for relative and degenerate Gromov--Witten invariants,
inspired by that of Jun 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.

Algebraic Geometry;Symplectic Geometry