Displaying similar documents to “On a problem of Nogura about the product of Fréchet-Urysohn $\langle \alpha_4\rangle$-spaces”

No hedgehog in the product?

Petr Simon, Gino Tironi (2002)

Commentationes Mathematicae Universitatis Carolinae

Similarity:

Assuming OCA, we shall prove that for some pairs of Fréchet α 4 -spaces X , Y , the Fréchetness of the product X × Y implies that X × Y is α 4 . Assuming MA, we shall construct a pair of spaces satisfying the assumptions of the theorem.