Research into the four-color theorem reached a turning point when Heinrich Heesch introduced the concept of discharging, a method that became essential for future computer-assisted proofs. Born in 1906 in Kiel, Germany, he dedicated his career to advancing mathematical theory within the fields of group theory, graph theory, and the geometry of tilings.
Academic Career and Political Climate
After receiving his education at the University of Zurich, Heesch held positions at the University of Göttingen. During his time there, he conducted research in group theory. In 1933, the political environment at the university shifted significantly due to National Socialist purges of academic staff. Refusing to join the required National Socialist organization for university teachers, he resigned from his post in 1935. He spent the following thirteen years conducting independent research on tilings while living at his parents' home in Kiel.
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Heesch returned to institutional academia in 1955, taking a position at Leibniz University Hannover. During this period, he focused his efforts on graph theory and the long-standing four-color problem. He developed the discharging method, a technique that proved fundamental for later verification efforts. Between 1967 and 1971, he visited the United States to access superior computing facilities, collaborating with Wolfgang Haken at the University of Illinois at Urbana-Champaign, as well as Karl Durre and Yoshio Shimamoto at the Brookhaven National Laboratory. Despite the DFG cancelling his funding during the project, he continued his work.
Contributions and Legacy
Following the 1977 success of Kenneth Appel and Wolfgang Haken in finalizing the four-color theorem proof, Heesch dedicated time to refining and shortening their results. His professional output included publications such as "Flächenschluß," co-authored with Otto Kienzle in 1963, and his 1969 work, "Untersuchungen zum Vierfarbenproblem." A collection of his treatises, "Gesammelte Abhandlungen," was published in 1986. Heesch remained a professor until his retirement and died in Hanover in 1995.
Fast facts
- Born: 1906, Kiel, Germany
- Died: 1995, Hanover, Germany
- Primary Field: Mathematics
- Education: University of Zurich
- Key Academic Affiliations: University of Göttingen, Leibniz University Hannover
Questions readers ask
What was Heinrich Heesch's role in the four-color theorem?
He developed the discharging method, which became a foundational component of the eventual computer-aided proof.
Why did Heesch leave the University of Göttingen in 1935?
He resigned after refusing to join the National Socialist organization of university teachers.
Achievements
- Held posts at Leibniz University Hannover and University of Göttingen
