Borsuk's quasi-equivalence relation on the class of all compacta is considered. The open problem concerning transitivity of this relation is solved in the negative. Namely, three continua X, Y and Z lying in ℝ³ are constructed such that X is quasi-equivalent to Y and Y is quasi-equivalent to Z, while X is not quasi-equivalent to Z.
@article{bwmeta1.element.bwnjournal-article-doi-10_4064-fm197-0-9, author = {Andrzej Kadlof and Nikola Kocei\'c Bilan and Nikica Ugle\v si\'c}, title = {Borsuk's quasi-equivalence is not transitive}, journal = {Fundamenta Mathematicae}, volume = {193}, year = {2007}, pages = {215-227}, zbl = {1144.54011}, language = {en}, url = {http://dml.mathdoc.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-fm197-0-9} }
Andrzej Kadlof; Nikola Koceić Bilan; Nikica Uglešić. Borsuk's quasi-equivalence is not transitive. Fundamenta Mathematicae, Tome 193 (2007) pp. 215-227. http://gdmltest.u-ga.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-fm197-0-9/