9,362 reputation
22070
bio website math.berkeley.edu/~schweber
location
age
visits member for 5 years
seen 3 hours ago

A graduate student at UC-Berkeley, interested in mathematical logic - specifically, computability theory and reverse mathematics, set theory, and abstract model theory. I'm also interested in other Nifty Things, in mathematics and elsewhere.


2d
answered History of unstable formulas
2d
accepted On the global structure of the Gromov-Hausdorff metric space
2d
comment On the global structure of the Gromov-Hausdorff metric space
This is very nice, thank you!
2d
awarded  Nice Question
Jul
29
revised The status of 'the consistency of NF relative to ZF'
added 69 characters in body
Jul
28
revised The status of 'the consistency of NF relative to ZF'
added 37 characters in body
Jul
28
comment The status of 'the consistency of NF relative to ZF'
Oh, I was not aware of this - does he believe his argument may be fixable?
Jul
28
awarded  Necromancer
Jul
28
awarded  Revival
Jul
28
answered The status of 'the consistency of NF relative to ZF'
Jul
28
comment Class forcings and elementary embeddings
(But I might be misunderstanding what you're asking - what do you mean by "relativized to a predicate"?)
Jul
28
comment Class forcings and elementary embeddings
@ThomasBenjamin Certainly not - for example, consider the trivial forcing extension $V[G]=V$. Truth in $V$ is very much not definable in $V[G]$. :P More generally, I suspect that it is much harder (if possible at all) to build a class- or set-generic extension $V[G]$ in which $Th(V)$ is definable. (Note that there's an apparent proof of impossibility: since the forcing relation is definable in $V$, shouldn't $Th(V[G], G)$ be definable in $V[G]$ from the parameter $G$ if $Th(V)$ is definable in $V[G]$? However, this breaks down since the forcing relation is not uniformly definable.)
Jul
27
awarded  Electorate
Jul
27
revised Numbers, multiplication and subtraction
edited tags
Jul
27
comment Recent progress on the busy beaver problem?
Maybe the OP is asking about computing small values of the Busy Beaver function?
Jul
27
comment The space of all compact metric spaces with Gromov-Hausdorff distance
I believe the set of finite metric spaces with pairwise rational distances is dense in the Gromov-Hausdorff space of compact metric spaces.
Jul
27
comment On the global structure of the Gromov-Hausdorff metric space
The space $\mathcal{GH}$ is known to be geodesic; beyond that, I don't know much.
Jul
27
revised Class forcings and elementary embeddings
added 56 characters in body
Jul
27
answered Class forcings and elementary embeddings
Jul
27
comment Class forcings and elementary embeddings
@ThomasBenjamin No - the embedding $j$ will send things in $V$ to things outside $V$. Note that this requires $V$ to not be definable in $V[G]$, which is where set forcing is different.