Institute of Mathematics and Informatics Bulgarian Academy of Sciences
Serdica Mathematical Journal, Vol. 24, No 3-4, (1998), 307p-318p
We prove that, for every countable ordinal α ≥ 3, there exists
countable completely regular spaces Xα and Yα such that the spaces Cp (Xα )
and Cp (Yα ) are borelian of class exactly Mα , but are not homeomorphic.