Guillermo was born in Ebéjico (Antioquia) and studied Mathematics at the National University, Bogotá. His graduate studies and first academic experiences took place in top-level universities: Southern California and Princeton in the USA, Politécnico Nacional in Mexico and the University of Puerto Rico.
In 1970, Guillermo joined the Department of Mathematics of Universidad del Valle. As teacher's representative, he took part in the massive mobilization of 1971: the movement’s archives still preserve his interventions in the professor's council and in the general assembly. The newbie professor confronted a convulsed conjuncture that definitely marked his life.
Since these years, Guillermo Restrepo Sierra became a true symbol of the University, of its democratic reserves and its struggles to build autonomy. In a complex context, among State terror and fragmentation of students’ organizations, there was only one professor who was respected and admired by the whole University community. How to explain this? The reasons were obvious: for years, Guillermo was the democratic guide of the Universidad del Valle. Through forums, assemblies, meetings and marches, professor Restrepo always was a reference for everyone: he was permanently ready to discuss, to teach and to build resistance.
Years ago, I knew him in the corridors of the University. Guillermo, a firm communist, was taking part in the heated discussions of the University, working without any prevention with a broad range of political afiliations: camilistas, maoists, anarchists. Surprisingly, he was respected by all the leaders of these political groupings, and also by trade union leaders and the University’s administration.
The lessons of his speeches and presentations keep imprinted in my memory: his admiration for the revolutionary priest Camilo Torres Restrepo, his theses on the relationship between the idea of communism and the philosophy of the first Christians, his deep respect for the Soviet people and the International Communist Movement and his insistence on linking social struggles and intellectual reflections.
Guillermo once gave us one of the best definitions of what a revolutionary party is. Describing the courageous struggles of the people of Stalingrad during the Nazi occupation, where civil population, communist militancy and Army officers victoriously resisted united, the professor said: “Party is the convergence of wills”.
Another day, a massive assembly were doing a political control to a University rector. An anarchist student took a lump of dog's excrement and left it on the rector's table. Guillermo, respectful as usual, stood up and personally took away the lump. For him, being a opposer didn't mean being irrespectful.
But the vital transcendence of Guillermo Restrepo Sierra goes beyond his political life. He was a remarkable mathematician whose contributions have revolutionized science in Colombia, particularly in the fields of differential equations and functional analysis. Also, he played a crucial role in the development of the Math Department of the Universidad del Valle and its specialized and advanced study programs.
But his marvelous efforts don't stop there. The Campus will bear the stamp of this pedagogue for many years. Many science students remember how Guillermo was always ready to help solving mathematical problems; any time, any place. His pedagogic capabilities allowed him to explain easily the most complex issues, sharing his knowledge without any selfishness. Entire generations of students are grateful for his lessons and recommendations in the most diverse fields of knowledge.
Finally, we should remember Guillermo's permanent support for a political solution to the Colombian conflict. As an organic intellectual, he always worked for the consolidation of an alternative to the longlasting Colombian war. During his last months, Guillermo raised his voice to defend the Havana peace process and to gain people for the possibility of a better future for our country. The achievement of peace, as a convergence of wills, will be his victory as well.