Journal of Geometry

, Volume 8, Issue 1, pp 171–186

S-functions for graphs

  • Rudolf Halin

DOI: 10.1007/BF01917434

Cite this article as:
Halin, R. J Geom (1976) 8: 171. doi:10.1007/BF01917434


S-functions are mappings from the class of finite graphs into the set of integers, such that certain formal conditions are fulfilled which are shared by the chromatic number, the vertex-connectivity, and the homomorphism-degree. The S-functions form a complete lattice (with respect to their natural partial order). The classes of graphs with values <n under some S-function are studied from a general point of view, and uncountably many S-functions are constructed. Further for every n≥5 a non-trivial base-element of
(see K. WAGNER [7]) is constructed.

Copyright information

© Birkhäuser Verlag 1976

Authors and Affiliations

  • Rudolf Halin
    • 1
  1. 1.Mathematisches Seminar der Universität2 Hamburg 13

Personalised recommendations