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seen Apr 15 at 19:10

Mar
18
comment A souped-up version of a question asked previously about uncountable subsets of topological spaces
Thanks. That certainly proves that property P does not imply second countability and one can take any second countable topological space for X.
Mar
17
comment A souped-up version of a question asked previously about uncountable subsets of topological spaces
I must apologize! My previous comment is topsy-turvy. X should be the space that has property P and Z should be the countable space that is not second countable. But I would still like to know what is meant by the "topological sum" of these two spaces.
Mar
17
comment A souped-up version of a question asked previously about uncountable subsets of topological spaces
@ Santi Sparado: Thanks for your answer. Perhaps you could clarify one point. Let Z be the space having property P. Is Y the set union of X and Z and is the set union of any base of X with any base of Z, a base of Y? I am just trying to understand clearly what "topological sum" means
Mar
16
asked A souped-up version of a question asked previously about uncountable subsets of topological spaces
Mar
6
awarded  Yearling
Feb
9
comment A question about tiling Hilbert Space
@Alexander Shamov: Thanks alot. That is very nice and I am amazed because I thought the answer would be negative.
Feb
9
accepted A question about tiling Hilbert Space
Feb
8
asked A question about tiling Hilbert Space
Jan
11
comment Is there a simple topological proof for a topological theorem about $S^2$?
@ Ian and Sasha: Very nice! That is exactly what I was looking for. Quantum theorists prefer the proofs based on finite sets of points since these points can represent directions of "spin" of a particle which are being measured in an experiment. But the coloring theorem is almost purely topological, except for the "metric" stipulation involving "pi/2". So I was sure it would have a proof of the kind you have provided. Unfortunately I was not able to come up with such a proof myself. Many thanks.
Jan
11
accepted Is there a simple topological proof for a topological theorem about $S^2$?
Jan
10
asked Is there a simple topological proof for a topological theorem about $S^2$?
Jan
1
comment A question about the Ordinal Definable elements of Power Sets
@Joel: Many thanks for answering all my questions and providing background that goes far beyond my rudimentary knowledge of forcing. My feeling about ordinal definability stems from my preference for set theories in which many undefinable sets exist (particularly undefinable real numbers). Intuitively, the languages in which most set theories are formalized contain only countably many formulae that can be used to define these sets. So I would like the class OD to be as small as possible. It seems to me rather counter-intuitive for all sets to be definable-which is what occurs with V=OD.
Dec
31
accepted A question about the Ordinal Definable elements of Power Sets
Dec
30
asked A question about the Ordinal Definable elements of Power Sets
Dec
13
comment Some questions about functions of Ordinal Numbers
Thanks alot for all this information. I asked these questions in order to obtain a clearer intuitive picture of the set of admissible ordinal numbers, which is often defined in rather complicated ways.
Dec
13
comment Some questions about functions of Ordinal Numbers
Thanks alot for all this information. I asked these questions in order to get a clearer intuitive picture of
Dec
13
accepted Some questions about functions of Ordinal Numbers
Dec
12
asked Some questions about functions of Ordinal Numbers
Dec
8
awarded  Popular Question
Dec
7
awarded  Nice Question