We will show that if a proper complete CAT(0) space X has a visual boundary homeomorphic to the join of two Cantor sets, and X admits a geometric group action by a group containing a subgroup isomorphic to ℤ2, then its Tits boundary is the spherical join of two uncountable discrete sets. If X is geodesically complete, then X is a product, and the group has a finite index subgroup isomorphic to a lattice in the product of two isometry groups of bounded valence bushy trees.
Keywords: CAT(0) space, CAT(0) group, Cantor set, join, spherical join, Tits boundary, visual boundary
Chao, Khek Lun Harold  1
@article{10_2140_agt_2014_14_1107,
author = {Chao, Khek Lun Harold},
title = {CAT(0) spaces with boundary the join of two {Cantor} sets},
journal = {Algebraic and Geometric Topology},
pages = {1107--1122},
year = {2014},
volume = {14},
number = {2},
doi = {10.2140/agt.2014.14.1107},
url = {http://geodesic.mathdoc.fr/articles/10.2140/agt.2014.14.1107/}
}
TY - JOUR AU - Chao, Khek Lun Harold TI - CAT(0) spaces with boundary the join of two Cantor sets JO - Algebraic and Geometric Topology PY - 2014 SP - 1107 EP - 1122 VL - 14 IS - 2 UR - http://geodesic.mathdoc.fr/articles/10.2140/agt.2014.14.1107/ DO - 10.2140/agt.2014.14.1107 ID - 10_2140_agt_2014_14_1107 ER -
Chao, Khek Lun Harold. CAT(0) spaces with boundary the join of two Cantor sets. Algebraic and Geometric Topology, Tome 14 (2014) no. 2, pp. 1107-1122. doi: 10.2140/agt.2014.14.1107
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