In every infinite-dimensional Fréchet space X, we construct a linear subspace E such that E is an -subset of X and contains a retract R so that is not homeomorphic to . This shows that Toruńczyk’s Factor Theorem fails in the Borel case.
@article{bwmeta1.element.bwnjournal-article-doi-10_4064-fm175-1-3,
author = {Tadeusz Dobrowolski and Witold Marciszewski},
title = {Failure of the Factor Theorem for Borel pre-Hilbert spaces},
journal = {Fundamenta Mathematicae},
volume = {173},
year = {2002},
pages = {53-68},
zbl = {1019.57012},
language = {en},
url = {http://dml.mathdoc.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-fm175-1-3}
}
Tadeusz Dobrowolski; Witold Marciszewski. Failure of the Factor Theorem for Borel pre-Hilbert spaces. Fundamenta Mathematicae, Tome 173 (2002) pp. 53-68. http://gdmltest.u-ga.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-fm175-1-3/