Camillo Costantini
On a problem of Nogura about the product of Fr\'echet-Urysohn $\delimiter "426830A \alpha _4\delimiter "526930B $-spaces

Comment.Math.Univ.Carolinae 40,3 (1999) 537-549.

Abstract:Assuming Martin's Axiom, we provide an example of two Fr\'echet-Urysohn $\delimiter "426830A \alpha _4\delimiter "526930B $-spaces, whose product is a non-Fr\'echet-Urysohn $\delimiter "426830A \alpha _4\delimiter "526930B $-space. This gives a consistent negative answer to a question raised by T. Nogura.

Keywords: Fr\'echet-Urysohn space, $\delimiter "426830A \alpha _4\delimiter "526930B $-space, Martin's Axiom, almost disjoint functions, double iterated power
AMS Subject Classification: Primary 54D55; Secondary 54G15, 54B10, 54D80, 03E50