Rudolf Halin

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Rudolf Halin (February 3, 1934 – November 14, 2014) was a German graph theorist, known for defining the ends of infinite graphs,[1] for Halin's grid theorem,[2][3] for extending Menger's theorem to infinite graphs,[4] and for his early research on treewidth and tree decomposition.[5] He is also the namesake of Halin graphs, a class of planar graphs constructed from trees by adding a cycle through the leaves of the given tree; earlier researchers had studied the subclass of cubic Halin graphs but Halin was the first to study this class of graphs in full generality.[6]

Life

Halin was born on February 3, 1934, in Uerdingen.[7] He earned his doctorate from the University of Cologne in 1962, under the supervision of Klaus Wagner and Karl Dörge, after which he joined the faculty of the University of Hamburg.[8] He died on November 14, 2014, in Mölln, Schleswig-Holstein.[7]

Recognition

In February 1994, a colloquium was held at the University of Hamburg in honor of Halin's 60th birthday.[9] In 2017, a special issue of the journal Abhandlungen aus dem Mathematischen Seminar der Universität Hamburg was published in his memory.[10]

Selected publications

Research papers

  • Halin, R. (1964), "Über unendliche Wege in Graphen",
    S2CID 122125458
    .
  • Halin, R. (1965), "Über die Maximalzahl fremder unendlicher Wege in Graphen", .
  • Halin, R. (1971), "Studies on minimally n-connected graphs", Combinatorial Mathematics and its Applications (Proc. Conf., Oxford, 1969), London: Academic Press, pp. 129–136, .
  • Halin, R. (1974), "A note on Menger's theorem for infinite locally finite graphs", Abhandlungen aus dem Mathematischen Seminar der Universität Hamburg, 40: 111–114, .
  • Halin, R. (1976), "S-functions for graphs", Journal of Geometry, 8 (1–2): 171–186, .

Textbooks

References

  1. ^ Halin (1964).
  2. ^ Halin (1965).
  3. S2CID 124603912
    .
  4. ^ Halin (1974).
  5. ^ Halin (1976).
  6. ^ Halin (1971).
  7. ^ a b Diestel, Reinhard (December 7, 2014), Rudolf Halin 1934–2014, DMANET mailing list. Date corrected in a follow-up email from Diestel. Birthplace from his books Graphentheorie I, II.
  8. ^ Rudolf Halin at the Mathematics Genealogy Project
  9. ^ Mathematisches Seminar, Univ. of Hamburg, retrieved 2013-02-19.
  10. .
  11. .