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Jun
11 |
awarded | Nice Answer |
Jul
2 |
awarded | Curious |
Jun
25 |
awarded | Revival |
Mar
22 |
comment |
Maximal ideals of the rings of Baire-One Functions
Isn't $Ba_1(X)$ a commutative C*-algebra (in which case it is certainly a PM-ring)? |
Mar
21 |
awarded | Yearling |
Jul
20 |
comment |
Characterizing Posets by Functions Into Natural Numbers
@Nik. What I had in mind amounts to taking finite subsets of the set of prime numbers whereas you are allowing arbitary subsets. (Actually in $Z$ shouldn't you be including the zero ideal as a prime ideal, so that $P$ isn't an unordered set?) Your approach seems to jettison the topology that is available if $P$ is a poset of prime ideals. But I suppose that not every poset is a poset of prime ideals of a ring? |
Jul
19 |
comment |
Characterizing Posets by Functions Into Natural Numbers
Presumably in the case when $P$ is the poset of prime ideals of a ring, $P^∗$ is isomorphic to the lattice of semiprime ideals? |
Jul
18 |
accepted | countably complete filters |
Jun
30 |
comment |
countably complete filters
Thanks. I will have to think about this. Presumably the definition of a Lindelof element is not quite right? |
May
22 |
answered | About subspaces of $F$-spaces |
May
16 |
comment |
iterating ultrapowers of C*-algebras: the Calkin algebra
Many thanks. Fascinating! |
May
16 |
accepted | iterating ultrapowers of C*-algebras: the Calkin algebra |
May
11 |
comment |
F-spaces and points whose complements are C*-embedded
Thanks. A more complicated problem than I realised! Is it known what the situation is for Shelah's model with no P-points? |
May
11 |
accepted | F-spaces and points whose complements are C*-embedded |
May
10 |
asked | F-spaces and points whose complements are C*-embedded |
May
9 |
revised |
iterating ultrapowers of C*-algebras: the Calkin algebra
corrected tags |
May
9 |
asked | iterating ultrapowers of C*-algebras: the Calkin algebra |
May
9 |
accepted | iterating ultrapowers of C*-algebras |
May
2 |
comment |
iterating ultrapowers of C*-algebras
I now understand from Nik's answer that the natural containment is strict at each stage, so in this sense the process never stabilizes. On the other hand, as far as constructing new C*-algebras is concerned, the process 'stabilizes' as soon at the ultrapower is isomorphic as a C*-algebra to its predecessor. So I am very interested in this question of whether $A^1$ and $A^2$ are C*-isomorphic (under CH). |
May
2 |
comment |
closed meagre sets
Thanks for this: it gives an easy way of visualizing a meagre subset of $C$. |