325 reputation
29
bio website maths.swan.ac.uk/staff/ejb
location Swansea, Wales
age
visits member for 2 years, 7 months
seen Jun 27 at 23:50

Jun
27
comment allowing `discontinuous functions' into a C* algebra
Very interesting... I shall have to look further into this, thanks for pointing it out.
Jun
27
accepted allowing `discontinuous functions' into a C* algebra
May
8
answered Example of a covariant derivative on a non-projective bundle
May
8
revised Example of a covariant derivative on a non-projective bundle
for clarity
May
8
comment Example of a covariant derivative on a non-projective bundle
Thanks - there is no chance for a locally trivial bundle to do this. But is there any sheaf-like structure (expressed as a module with connection over the algebra of functions) for which it can be done?
May
8
asked Example of a covariant derivative on a non-projective bundle
May
8
awarded  Benefactor
May
6
accepted Identifying a Hopf algebra cohomology theory
May
2
comment Identifying a Hopf algebra cohomology theory
OK, I have added more explanation - apologies for that. There is a way to reformulate the complex with no explicit invariants and no algebra structure.
May
2
revised Identifying a Hopf algebra cohomology theory
better explanation of problem
May
2
comment Identifying a Hopf algebra cohomology theory
The required action for the van Est spectral sequence is the full tensor product coaction (this is needed to get a non-trivial dependence on the coaction). I see now that my question was ambiguous on this point. If I remember correctly, the sequence without taking the invariants is acyclic - will check.
May
1
comment Identifying a Hopf algebra cohomology theory
The product appears implicitly in the coaction on the tensor product. I am checking the reference - thanks!
May
1
awarded  Promoter
Apr
18
awarded  Yearling
Apr
18
revised Identifying a Hopf algebra cohomology theory
spelling!
Apr
17
asked Identifying a Hopf algebra cohomology theory
Mar
5
comment How rigid can a rigid object be in GR?
That is a good way of thinking about it - and may well give a method for finding the answer.
Mar
4
comment How rigid can a rigid object be in GR?
The problem is, what if we cannot start in flat space? What is the best that we can do with the coordinate system? The black hole is just an example of a localised curvature - the details are not important.
Mar
4
comment How rigid can a rigid object be in GR?
There is a coordinate system which is formed by taking a 3D space like submanifold, and declaring it to be time zero, and then taking the geodesic motion in 4D perpendicular to the submanifold, with time coordinate proper time. This gives a nicely behaved coordinate system, at least locally. If we can start in flat space, and then move into more complicated geometry, we can set an initial metric on the 3D slice to be the usual Euclidian metric.
Mar
4
comment How rigid can a rigid object be in GR?
The question is a bit ambiguous, but I was hoping that there was an existing body of literature, and I did not want to make it too restrictive.