High energy interactions on nuclei

Multihadron production and coherent or semicoherent reactions on nuclei allow information about such intriguing topics as space-time development of particle production and interactions of resonances with nucleons. Some of the latest results are here summarized, with particular emphasis on the coherent and semicoherent channels, in connection with the criticisms and suggestions recently developed regarding the so called sigma /sub 2/ cross-section (for the interactions of resonances with nucleons), as it is obtained from the A dependence of diffractive production on nuclei. (34 refs).