Mathematics

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Apr 24, 2020 13:33
@Astyx here this is where I learned about all this stuff
Apr 24, 2020 13:27
Sheaf cohomology is very useful
Apr 24, 2020 13:26
you can compute sheaf cohomology for instance
Apr 24, 2020 13:25
@Astyx what do you want to ask about sheaf cohomology ?
Apr 24, 2020 13:23
@Astyx I can help you out I know about sheaf cohomology
Apr 24, 2020 13:22
is it true that the commutant of U is proper subset of M ?
Apr 24, 2020 13:22
let U be the set of all upper triangular matrices
Apr 24, 2020 13:22
I think the commutant of 2x2 upper triangular matrices is subset of m ?
Apr 24, 2020 13:21
yeah
Apr 24, 2020 13:14
does anyone know whether upper triangular matrices are weak operator closed ?
Apr 24, 2020 11:37
does anyone know the the bicommutant group of upper triangular matrices ?
Mar 27, 2020 14:36
@AlessandroCodenotti where r u from btw ?
Mar 27, 2020 14:36
@AlessandroCodenotti do you agree?
Mar 27, 2020 14:35
Yeah I mean through this identification everything works out
Mar 27, 2020 14:31
for H hilbert space
Mar 27, 2020 14:30
you can identify nxn entries with elements in B(H) by Mn(H^n)
Mar 27, 2020 14:25
I am pretty sure this is correct
Mar 27, 2020 14:24
I want to ask let us say we have a net $(A_{\lambda}) in M_n(B(H)) = M_n(H^{n})$ for hilbert space H.
therefore the net A_lambda --> 0 iff a_i,j --> 0 for all i,j by identifying Mn(B(H)) with Mn(H^{n}) right?
Mar 26, 2020 04:06
it is a simple question actually
Mar 26, 2020 04:06
banach space ?
Mar 26, 2020 04:05
hi @LeakyNun are you familiar with C* algebra?
Aug 25, 2018 01:41
brb
Aug 25, 2018 01:38
I always rely on my brain for everything
Aug 25, 2018 01:38
what I am missing now @TedShifrin is some organizational skills.
Aug 25, 2018 01:32
I have improved on that.
Aug 25, 2018 01:31
the reason I covered a lot is because I wanted to be prepared for my PhD that is all.
Aug 25, 2018 01:30
besides this is not PhD thesis it is just MSc thesis.
Aug 25, 2018 01:30
just doing revisions atm
Aug 25, 2018 01:30
I mean I am done already
Aug 25, 2018 01:29
thx
Aug 25, 2018 01:29
glad your enjoying your measure theory book.
Aug 25, 2018 01:29
don't worry I mean I don't really take this personal it is okay
Aug 25, 2018 01:28
yeah I will remove certain aspects of it.
Aug 25, 2018 01:27
unless you have my thesis you can't say that.
Aug 25, 2018 01:27
How do you know @DrewBrady ?
Aug 25, 2018 01:26
yeah I agree
Aug 25, 2018 01:25
yeah I agree.
Aug 25, 2018 01:25
Yeah I mean my thesis is already 350 pages.
Aug 25, 2018 01:23
yeah I will remove it
Aug 25, 2018 01:23
your right
Aug 25, 2018 01:23
yeah
Aug 25, 2018 01:23
and I know the result which state that topological K-theory over X is the same as K-theory of coherent sheaves on X.
Aug 25, 2018 01:22
$K_0(X)$ here being the K-theory of coherent sheaves on X.
Aug 25, 2018 01:22
I know that G-R-R gives us somehow the isomorphism above. I don't know the details though.
Aug 25, 2018 01:20
I don't know the details of the explicit isomorphisms involved.
Aug 25, 2018 01:20
Grothiendieck-Riemann-Roch gives us $K_0(X) \otimes Q \cong A(X) \otimes Q$
Aug 25, 2018 01:19
sorry adjusted.
Aug 25, 2018 01:18
$K_0(X) \otimes Q \cong A(X) \otimes Q$
Aug 25, 2018 01:18
Because of Grothiendieck-Riemann-Roch