He was the leader of the Finnish Centre of Excellence in Inverse Problems Research and the director of the Rolf Nevanlinna Institute and the section of applied mathematics at the University of Helsinki.
[1] Päivärinta was awarded the Magnus Ehrnrooth Foundation Prize in mathematics by the Finnish Society of Sciences and Letters in 2006.
Since the late 1980s, inverse problems have attracted rapidly growing research interest, mostly in applied but also in pure mathematics.
Päivärinta is one of the leading figures in this development from an early stage,[4][5] and his research interests range from mathematical theory to practical applications.
[8] The problem has immediate application in electrical impedance tomography (EIT), a means of imaging the interior of the human body.