On a condition for the pseudo radiality of a product
A sufficient condition for the pseudo radiality of the product of two compact Hausdorff spaces is given.
A sufficient condition for the pseudo radiality of the product of two compact Hausdorff spaces is given.
In this paper, we give an affirmative answer to the problem posed by Y. Tanaka and Y. Ge (2006) in "Around quotient compact images of metric spaces, and symmetric spaces", Houston J. Math. 32 (2006) no. 1, 99-117.
The definitions of AP and WAP were originated in categorical topology by A. Pultr and A. Tozzi, Equationally closed subframes and representation of quotient spaces, Cahiers Topologie Géom. Différentielle Catég. 34 (1993), no. 3, 167-183. In general, we have the implications: , where is defined as the property that every compact subset is closed and is defined as the property that every convergent sequence has at most one limit. And a space is called submaximal if every dense subset is open....
Following Kombarov we say that is -sequential, for , if for every non-closed subset of there is such that and . This suggests the following definition due to Comfort and Savchenko, independently: is a FU()-space if for every and every there is a function such that . It is not hard to see that ( denotes the Rudin–Keisler order) every -sequential space is -sequential every FU()-space is a FU()-space. We generalize the spaces to construct examples of -sequential...
In this article we introduce the notion of strongly -spaces, that is, those spaces in which countably compact subsets are closed. We find they have good properties. We prove that a space is maximal countably compact if and only if it is minimal strongly , and apply this result to study some properties of minimal strongly -spaces, some of which are not possessed by minimal -spaces. We also give a positive answer to a question proposed by O. T. Alas and R. G. Wilson, who asked whether every...
It is shown that a space is -Weakly Fréchet-Urysohn for iff it is -Weakly Fréchet-Urysohn for arbitrary , where is the -th left power of and for . We also prove that for -compact spaces, -sequentiality and the property of being a -Weakly Fréchet-Urysohn space with , are equivalent; consequently if is -compact and , then is -sequential iff is -sequential (Boldjiev and Malyhin gave, for each -point , an example of a compact space which is -Fréchet-Urysohn and it is...