Montero De Juan, Francisco JavierVitoriano Villanueva, BegoñaGómez González, DanielLu, JieKerre, Etienne E.2023-06-202023-06-202013Montero, J., Vitoriano, B., Gómez, D.: Professor Da Ruan, Distinguished Visitor at Complutense University, Madrid. En: Lu, J. y Kerre, E. (eds.) A Tribute to Prof. Dr. Da Ruan. pp. 139-141. Springer Berlin Heidelberg, Berlin, Heidelberg (2013)978-3-642-30306-710.1007/978-3-642-30307-4_25https://hdl.handle.net/20.500.14352/45582This short note is written as a contribution to the memory of Prof. Da Ruan. We shall try to reflect how he was entitled to stay two months (April-May 2011) as “Distinguisher Visitor” at Complutense University, Madrid, based upon his past collaborations without team, and pointing out some of the projects we jointly developed and launched during such a period. Beside the strictly scientific arguments towards his academic excellence, we want to stress his continuous support to explore new initiatives from a sincere and friendly collaboration.engbook parthttps//doi.org/10.1007/978-3-642-30307-4_25http://link.springer.com/chapter/10.1007%2F978-3-642-30307-4_25open access51Matemáticas (Matemáticas)12 Matemáticas