Vol. 5 Num. 1, 1992

On vector fields in C³ without a separatrix
Christian LÉGER
Erratum: Opérations sur les cartes et métamorphoses de la catégorie des G-ensambles
Ary O. CHIACCHIO, João B. PROLLA, and Maria S. ROVERSI Best approximants for bounded functions and lattice operations
Alberto BOROBIA and Ujué R. TRÍAS
A geometric proof of the Perron-Frobenius theorem
  Javier LAFUENTE LÓPEZ Conos de luz
 Serge NICAISE Exact controllabity of a pluridimensional coupled problem
Jose Francisco RODRIGUES On a quasi-variational inequality arising in semiconductor theory