RT Journal Article T1 Controllability of star-shaped networks of strings A1 Zuazua Iriondo, Enrique A1 Dáger Salomón, René AB In this note we consider a star-shaped network of vibrating strings. The problem of controllability when one control acts on the junction point is considered. A simple proof is given that, in particular, does not use Ingham inequalities, of the fact that the set of reachable data is dense, whenever the lengths of the strings are mutually irrational. The proof is based on an observability inequality with suitable weights on the Fourier coefficients that is easily obtained as a consequence of the time-periodicity of the solutions. Those weights can be estimated under certain algebraicity conditions imposed on the lengths of the strings. This allows to proof exact controllability results in Sobolev spaces of appropriate order. Further results are also presented concerning the control from a free end and diffusion processes. PB Elsevier SN 0764-4442 YR 2001 FD 2001-04-01 LK https://hdl.handle.net/20.500.14352/56998 UL https://hdl.handle.net/20.500.14352/56998 LA eng NO DGES NO EU TMR DS Docta Complutense RD 16 abr 2025