In this note I try to clarify the problem of perturbations in the ekpyrotic
universe. I write down the most general matching conditions and specify the
choices taken by the two debating sides. I also bring up the problem of surface
stresses which always have to be present when a transition from a collapsing to
an expanding phase is made.Comment: 3 pages, no figures Some typo's and a conceptial mistake corrected.
Conclusions unaltere
