Geodesic
(Co)-homologie von Graphen and Invarianten
Séminaire lotharingien de combinatoire, Tome 18 (1987) 
Ulrich Oberst. (Co)-homologie von Graphen and Invarianten. Séminaire lotharingien de combinatoire, Tome 18 (1987). http://geodesic.mathdoc.fr/item/SLC_1987_18_a18/
@article{SLC_1987_18_a18,
     author = {Ulrich Oberst},
     title = {(Co)-homologie von {Graphen} and {Invarianten}},
     journal = {S\'eminaire lotharingien de combinatoire},
     year = {1987},
     volume = {18},
     url = {http://geodesic.mathdoc.fr/item/SLC_1987_18_a18/}
}
TY  - JOUR
AU  - Ulrich Oberst
TI  - (Co)-homologie von Graphen and Invarianten
JO  - Séminaire lotharingien de combinatoire
PY  - 1987
VL  - 18
UR  - http://geodesic.mathdoc.fr/item/SLC_1987_18_a18/
ID  - SLC_1987_18_a18
ER  - 
%0 Journal Article
%A Ulrich Oberst
%T (Co)-homologie von Graphen and Invarianten
%J Séminaire lotharingien de combinatoire
%D 1987
%V 18
%U http://geodesic.mathdoc.fr/item/SLC_1987_18_a18/
%F SLC_1987_18_a18

Voir la notice de l'acte provenant de la source Séminaire Lotharingien de Combinatoire website

This article emeged from a two-hour lecture on graph theory for students with standard knowledge of algebra. It is known since Poincaré (keyword: Analysis situs) that graph theory can be conceived as 1- or at most 2-dimensional special case of combinatorial (today: algebraic) topology. Viewed in this way, the method of my lecture was the use of elementary homological algebra and of arbitrary coefficient groups in (co-)homology. I introduce - to my knowledge - new homological invariants of a graph, namely the invariant factors of the finite group Z{edges of G}/(B1(G)+H1(G)), and I derive some of their properties. Furthermore, I demonstrate the method of this lecture with the contraction and the Meyer-Vietoris sequence.

The paper has been finally published under the title "Some combinatorial properties of the Thue-Morse sequence and a problem in semigroups" in Theoret. Comput. Sci. 63 (1989), 333-348.