Hans-Joachim Bremermann

Hans-Joachim Bremermann (1926–1996) was a German-American mathematician and biophysicist. He worked on computer science and evolution, introducing ideas of how mating generates new gene combinations. Bremermann's limit, named after him, is the maximum computational speed of a self-contained system in the material universe.

Early life
Bremermann was born in Bremen, Germany, to Bernard Bremermann and Berta Wicke.

Bremermann undertook doctoral studies at the University of Münster, completing his Staatsexamen in mathematics and physics in 1951. In the same year, his doctoral dissertation Die Charakterisierung von Regularitätsgebieten durch pseudokonvexe Funktionen was published, in which he solved a special case of the Levi problem. He was to become a specialist in complex analysis.

Career
Bremermann came to the United States in 1952 and held a research associate position at Stanford University. In 1953, he was appointed a research fellow at Harvard University. He returned to Münster for 1954–55.

After returning to the United States, he was a mathematics researcher at the Institute for Advanced Study in Princeton (1955–57), and then appointed assistant professor at the University of Washington, Seattle (1957–58). He then spent another year researching at Princeton (1958–59), this time in physics.

In 1959, he became an associate professor of mathematics at University of California, Berkeley, where he remained for the rest of his career, being promoted to full professor in 1966. He held chairs at Berkeley in mathematics and biophysics. By the 1960s, his work had turned towards the theory of computation and evolutionary biology, in which he studied complexity theory, genetic search algorithms, and pattern recognition.

In 1978 he gave the "What Physicists Do" series of lectures at Sonoma State University, discussing physical limitations to mathematical understanding of physical and biological systems. He continued work in mathematical biology through the 1980s, developing mathematical models of parasites and disease, neural networks, and AIDS epidemiology and pathology. He retired from the University of California in 1991.

Personal life
On 16 May 1954, Bremermann married Maria Isabel Lopez Perez-Ojeda, a scholar of romance language and literature.

Legacy
R.W. Anderson writes:"[Bremermann] continued to develop mathematical modelling as a tool to understanding complex (especially biological) systems for the rest of his life. His intellectual journey was marked by brilliant insight and foresight. [...] Hans Bremermann is not only remembered for his genius but also for his warmth, generosity, courage, integrity, humility, and love."In 1995, a festschrift was published with a brief biography and 13 scientific papers of his former students and colleagues in a special issue of BioSystems.