A laterally commutative heap can be defined on a given set iff there is the structure of a TST-space on this set.
@article{urn:eudml:doc:38989,
title = {Laterally commutative heaps and TST-spaces.},
journal = {Stochastica},
volume = {11},
year = {1987},
pages = {229-233},
zbl = {0674.20045},
mrnumber = {MR0990886},
language = {en},
url = {http://dml.mathdoc.fr/item/urn:eudml:doc:38989}
}
Volenec, Vladimir. Laterally commutative heaps and TST-spaces.. Stochastica, Tome 11 (1987) pp. 229-233. http://gdmltest.u-ga.fr/item/urn:eudml:doc:38989/