Klaus Wagner (mathematician)

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Klaus Wagner (right) and Frank Harary in Oberwolfach in 1972

Klaus Wagner (born March 31, 1910 in Cologne- Klettenberg; † February 6, 2000 ) was a German mathematician . He is considered to be one of the pioneers of graph theory .

Life and career

Klaus Wagner was the youngest of four sons of the accountant and authorized signatory Christian Wagner. He attended the Realgymnasium in Cologne-Lindenthal and graduated from high school there in 1930 . He then studied mathematics , physics , chemistry and meteorology at the University of Cologne . Wagner was in 1934 Karl Dörge with the work over two sets of the topology: Jordan Curve Theorem and four color problem doctorate . As a post-doctoral student he was with Kurt Reidemeister at the University of Marburg .

After completing his studies, Wagner worked as a meteorologist at Cologne and Berlin airports and was also active in this function during the Second World War .

Wagner returned to mathematics after the end of the war and completed his habilitation in 1949 at the University of Cologne with the text Topological Treatment of the Fundamentals in Infinitesimal Calculus . There he became a scientific advisor and professor in 1956 . In 1970 he received a call to the University of Duisburg , whereupon the University of Cologne appointed him honorary professor in 1971 . In 1978 he retired .

Wagner lived in Cologne-Rath, had been married to Hanna Wagner since 1950 and had a son and a daughter.

His doctoral students include Rudolf Halin , Bruno Bosbach (Kassel), Heinz Jung (TU Berlin) and Egbert Harzheim .

Scientific achievements

The Wagner graph

Klaus Wagner made significant achievements in pure mathematics , not least in topology and graph theory, and in particular in the field of topological graph theory . Be highlighted results as the equivalent set of Wagner , the set of Wagner and the set of Wagner and Fary . The Wagner graph is named after Wagner . Likewise, the Wagnerian Hypothesis goes back to him , the proof of which was provided in 2004 by Neil Robertson and Paul Seymour , which is known as the Robertson-Seymour Theorem . It is a reformulation of Kuratowski's theorem by replacing topological minors (Kuratowski) with graph minors and was first formulated by Wagner in 1937.


In 1985, in honor of Klaus Wagner, the commemorative publication Graphs in Research and Education was published. In 1997, Wagner received an honorary doctorate from the University of Duisburg . In June 2000, a celebratory colloquium was held posthumously in his memory at the University of Cologne .


Klaus Wagner was the author or co-author of 62 scientific publications and 7 specialist books , not least the following much-cited textbook:

  • Klaus Wagner: Theory of graphs (=  BI university pocket books. 248 / 248a). Bibliographisches Institut, Mannheim (inter alia) 1970, ISBN 3-411-00248-4 .



Web links

Individual evidence

  1. Klaus Wagner in the Mathematics Genealogy Project (English)Template: MathGenealogyProject / Maintenance / id used
  2. ^ Wagner, On an expansion of Kuratowski's theorem, Deutsche Mathematik, Volume 2, 1937, pp. 280–285
  3. ^ Bill Casselman, Variations on Graph Minor, AMS