Gerhard Ringel (born October 28, 1919, Kolnbrunn, Austria) is a German mathematician who earned his Ph. Events 306 - Maxentius is proclaimed Roman Emperor. 312 - Battle of Milvian Bridge: Constantine Year 1919 ( MCMXIX) was a Common year starting on Wednesday (link will display the full calendar of the Gregorian calendar (or a Common A mathematician is a person whose primary area of study and research is the field of Mathematics. D. from the University of Bonn in 1951. The University of Bonn ( German: Rheinische Friedrich-Wilhelms-Universität Bonn) is a public research university located in Bonn, Germany He is one of the pioneers in graph theory and contributed significantly to the proof of the Heawood conjecture (now Ringel-Youngs theorem). The Heawood conjecture or Ringel–Youngs theorem in Graph theory gives an Upper bound for the number of colors which are Sufficient for The Heawood conjecture or Ringel–Youngs theorem in Graph theory gives an Upper bound for the number of colors which are Sufficient for
Gerhard Ringel spent much of his career at the University of California, Santa Cruz, where he also spent time surfing and collecting butterflies.
References
- Ringel, Gerhard; Youngs, J. W. T. (1968). "Solution of the Heawood map-coloring problem". Proc. Nat. Acad. Sci. USA 60: 438–445. doi:. A digital object identifier ( DOI) is a permanent identifier given to an Electronic document. MR0228378. Mathematical Reviews is a journal and online database published by the American Mathematical Society that contains brief synopses (and occasionally evaluations of many
- Hartsfield, Nora; Ringel, Gerhard (1990). Pearls in graph theory. Academic Press, Boston, MA. ISBN 0-12-328552-6.
External links
- Retired mathematics professor Gerhard Ringel gives his world-class butterfly collection to UCSC, UC Santa Cruz Review, Fall 2006
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