A new distributional approach to signature change

Colombeau's generalized functions are used to adapt the distributional appr oach to singular hypersurfaces in general relativity with signature change. Equations governing the dynamics of a singular hypersurface are derived an d a specific non-vanishing form for the energy-momentum tensor of the singu lar hypersurface is obtained. It is shown that matching in the case of de S itter space in the Lorentzian sector is possible along the boundary with mi nimum radius but leads to the vanishing of the energy-momentum tensor of th e singular hypersurface.