In this paper we represent every lattice by subgroups of free groups using the concept of the homotopy group of a graph.
@article{119077,
author = {Ji\v r\'\i\ T\r uma},
title = {Representing lattices by homotopy groups of graphs},
journal = {Commentationes Mathematicae Universitatis Carolinae},
volume = {40},
year = {1999},
pages = {215-221},
zbl = {0977.06003},
mrnumber = {1732642},
language = {en},
url = {http://dml.mathdoc.fr/item/119077}
}
Tůma, Jiří. Representing lattices by homotopy groups of graphs. Commentationes Mathematicae Universitatis Carolinae, Tome 40 (1999) pp. 215-221. http://gdmltest.u-ga.fr/item/119077/
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