Javier Chavarriga (Barcelona, 1957 - Lleida, 2005) was the founder of the research group SEMINARI DE SISTEMES DINÀMICS of the Universitat de Lleida. His research can be framed inside continuous dynamical systems and more in particular in the theory of planar autonomous ordinary differential equations. He remarkably contributed to the center-focus and the integrability problems. He also studied isochronous centers, reversibility, nilpotent and degenerate systems, Darboux integrability, bifurcations, limit cycles (Hilbert's 16th problem), Lie symmetries, differential equations in the complex projective plane, etc.
Extracted from the paper In memoriam published in "Notícies the la Societat Catalana de Matemàtiques, (23) pp. 11-15, 2007 (In Catalan)"