Talagrand compacta, 2DCP, and pointwise quotients
Abstract
We revisit Talagrand's CH compactum as a test object for the two-disjoint-copies property and for pointwise quotient questions. The two-disjoint-copies property, or 2DCP, is a topological sufficient condition for the existence of infinite-dimensional metrisable quotients of spaces ; recent work asks whether Talagrand's compactum has this property. Assuming for a stationary co-stationary , we carry out Talagrand's inverse-limit construction with additional diagonalisation. The resulting compactum keeps Talagrand's conclusions: is Grothendieck, the weak-star compact ball contains no copy of , and has no non-trivial convergent sequences. At the same time, no two disjoint non-metrisable closed subspaces of are homeomorphic; hence has no 2DCP and is not locally homogeneous. We also give a ZFC example of a perfect compact space with 2DCP which is not locally homogeneous and contains neither nor . Finally, we isolate a general locally convex observation, in the spirit of the Banakh--Gabriyelyan theory of the Josefson--Nissenzweig property, showing that pointwise quotients onto , , force the Josefson--Nissenzweig property. Consequently Talagrand compacta have no classical pointwise sequence quotients , , or . The full metrisable quotient problem for these -spaces remains open. Several open problems are included.
Cite
@article{arxiv.2607.06808,
title = {Talagrand compacta, 2DCP, and pointwise quotients},
author = {Tomasz Kania and Jerzy Kąkol},
journal= {arXiv preprint arXiv:2607.06808},
year = {2026}
}
Comments
19 pp