MiS Preprint Repository

We have decided to discontinue the publication of preprints on our preprint server as of 1 March 2024. The publication culture within mathematics has changed so much due to the rise of repositories such as ArXiV ( that we are encouraging all institute members to make their preprints available there. An institute's repository in its previous form is, therefore, unnecessary. The preprints published to date will remain available here, but we will not add any new preprints here.

MiS Preprint

Relations Between Graphs

Yangjing Long, Ling Yang, Peter F. Stadler and Jürgen Jost


Given two graphs G=(V_G,E_G) and H=(V_H,E_H), we ask under which conditions there is a relation that generates the edges of H given the structure of G. This construction generalizes full homomorphisms of graphs and naturally leads to generalized notions of retractions, cores, and co-cores of graphs.

MSC Codes:
05, C99
generalized graph homomorphism, R-core, R-retraction, binary relation

Related publications

2013 Journal Open Access
Jan Hubicka, Jürgen Jost, Yangjing Long, Peter F. Stadler and Ling Yang

Relations between graphs

In: Ars mathematica contemporanea, 6 (2013) 2, pp. 323-350