We prove that the Pontryagin sphere and the Pontryagin nonorientable surface occur as the Gromov boundary of a 7-systolic group acting geometrically on a 7-systolic normal pseudomanifold of dimension 3.
@article{bwmeta1.element.bwnjournal-article-doi-10_4064-fm207-1-4, author = {Pawe\l\ Zawi\'slak}, title = {Trees of manifolds and boundaries of systolic groups}, journal = {Fundamenta Mathematicae}, volume = {209}, year = {2010}, pages = {71-99}, zbl = {1275.20048}, language = {en}, url = {http://dml.mathdoc.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-fm207-1-4} }
Paweł Zawiślak. Trees of manifolds and boundaries of systolic groups. Fundamenta Mathematicae, Tome 209 (2010) pp. 71-99. http://gdmltest.u-ga.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-fm207-1-4/