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Apr
24 |
asked | Nonexistence of generic objects over $L(\mathbb{R})$ |
Mar
8 |
comment |
Is the set of subsequences of branches through a tree Borel?
Thanks Joel. While I don't need it at the moment, it might be nice to have a sketch of the argument for why the set can be complete analytic in the not-necessarily increasing case. |
Mar
8 |
accepted | Is the set of subsequences of branches through a tree Borel? |
Mar
8 |
asked | Is the set of subsequences of branches through a tree Borel? |
Feb
26 |
awarded | Nice Question |
Nov
29 |
comment |
An interpretation for filters of subspaces in Banach spaces
Yep, in fact, those results are exaclty the reason I posed the question. I'm particularly looking for interpretations in other spaces, like $\ell^p$ and $c_0$. |
Nov
28 |
asked | An interpretation for filters of subspaces in Banach spaces |
Nov
23 |
revised |
A property of uncountable almost disjoint families
Added parenthetical comment to Q2. |
Nov
23 |
awarded | Yearling |
Nov
23 |
revised |
A property of uncountable almost disjoint families
edited body |
Nov
23 |
revised |
A property of uncountable almost disjoint families
Added "Question 2". |
Nov
23 |
revised |
A property of uncountable almost disjoint families
Added note "EDIT" |
Nov
23 |
accepted | A property of uncountable almost disjoint families |
Nov
23 |
comment |
A property of uncountable almost disjoint families
@FedorPetrov I had a related application in mind, and this is all that was necessary. Certainly a witness in $\mathcal{A}$ would be fine. |
Nov
23 |
asked | A property of uncountable almost disjoint families |
Aug
27 |
comment |
When do block sequences yield disjoint subspaces?
Bill: I'm a bit unfamiliar with the terminology (Banach space theory is a outside my usual area), what do you mean by "minimal sequence" and "M-basis"? |
Aug
24 |
asked | When do block sequences yield disjoint subspaces? |
May
20 |
accepted | When is a filter generated by a (countable) chain? |
Apr
20 |
accepted | Existence of state on a C*-algebra satisfying $|\tau(ab)|=\|ab\|$ |
Apr
20 |
comment |
Classification of complex structures on $\mathbb{R}^{2n}$
This paper of Hjorth and Kechris may be of interest: projecteuclid.org/euclid.ijm/1255984956. It deals with using descriptive set theory to understand the classification problem for arbitrary Riemann surfaces (not just structures on $\mathbb{R}^{2n}$), and shows that even in complex dimension $1$, this is extremely complicated (the "moduli space" is "Borel equivalent" to the quotient of $\{0,1\}^{F_2}$ by the left shift action of the free group $F_2$). For higher dimensions, it is more complicated ("not classifiable by countable structure" in the subject's parlance). |