(b. 7 November 1928, Poznań; d. 11 October 2020, Poznań)
Musielak attended the private St. Kazimierz Primary School in Poznań from 1935 to 1939. During the war, in 1942–1945, he was employed as a manual worker. He then attended the Berger High School in Poznań, which specialised in mathematics and physics. From 1946 to 1951 he studied mathematics at Poznań University, and already in 1949 began research work there. He gained his doctorate (then called “candidate in mathematical sciences”) in 1958 under the supervision of Władysław Orlicz, and his habilitation degree in 1963. He became an associate professor in 1971, and a full professor in 1980. He was dean of Adam Mickiewicz University’s Faculty of Mathematics and Physics in 1981–1984, vice-rector of the university in 1984–1985, and director of the Institute of Mathematics in 1990–1993. He retired in 1999, but until 2006 continued to work part-time at the university. He did research in mathematical analysis, particularly functional analysis (Fourier series with respect to trigonometric and other orthogonal systems, constructive function theory, approximation theory, vector integrals, distribution theory, modular spaces, and linear and nonlinear integral operators). He published more than 200 works, among which were three monographs (including Orlicz Spaces and Modular Spaces, Springer Verlag 1983; and Nonlinear Integral Operators and Applications, Walter de Gruyter 2003, authored jointly with C. Bardaro and G. Vinti) and 13 textbooks (including an introduction to functional analysis, published by PWN in 1976, and – as co-author – a multiple-volume handbook of mathematical analysis). He was the supervisor of 36 successful doctoral students. He was among the inspirers and organisers of the Poznań school of research in functional spaces, and the concept of Musielak–Orlicz spaces has become established in functional analysis. He received many prizes and awards, including six ministerial prizes (in 1964, 1969, 1975, 1981, 1984 and 1988), the City of Poznań’s Scientific Prize (in 2004), and the Medal of the National Education Commission (in 1980). In 2000 he became an honorary member of the Polish Mathematical Society, and in 2008 he received an honorary doctorate from the University of Zielona Góra.
M. Jaroszewska, L. Skrzypczak, “Musielak Julian”, in: Luminarze nauki Uniwersytetu Poznańskiego 1919–2019, ed. Z. Pilarczyk, Wyd. Nauk. UAM, Poznań 2019, pp. 454–458.
L. Maligranda, W. Wnuk, 100 lat matematyki na uniwersytecie w Poznaniu 1919–2019, Wyd. Nauk. UAM, Poznań 2021, pp. 308–329 and 468–469.