Resumen
As a basic higher-order model, the fourth-order Boussinesq-type quasilinear wave equation (the QWE-4) is considered. Self-similar blow-up solutions are shown to exist that generate as t ? T- discontinuous shock waves. The QWE-4 is also shown to admit a smooth (for t > 0) global 'fundamental solution' i.e. having a measure as initial data. A 'homotopic' limit n ? 0 is used to get being the classic fundamental solution of the 1D linear beam equation