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Nov 20, 2018 at 15:13 history edited YCor
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S Nov 20, 2018 at 15:00 history suggested Christoph Mark CC BY-SA 4.0
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S Nov 20, 2018 at 15:00
Apr 17, 2012 at 8:44 answer added Nicola Ciccoli timeline score: 4
Apr 16, 2012 at 14:59 answer added Réamonn Ó Buachalla timeline score: 8
Apr 12, 2012 at 6:33 comment added Alexander Chervov equivalent to category of U(g) modules with twisted tensor product, the twisting can be constructed with the Drinfeld's associator.
Apr 12, 2012 at 6:32 comment added Alexander Chervov I also heard that U_q and U are isomorphic q=e^h and working over C[h], as I remember it mentioned in the Cartier's Bourbaki talks. As far as I understand reason is simple H^2(g) are trivial - so we cannot deform Lie algebra structure and this also implies we cannot deform U(g) is a reasonably non-trivial way. Another to look on it - let us look on the category of finite-dim representations of U(g) - it is semi-simple - so there is no deformation of the category structure, the only thing we can deform tensor product, this indeed can be done, and tensor category of U_q(g) modules is ...
Apr 12, 2012 at 5:33 comment added tzhang U(g) and Uq(g) are different as algebras and coalgebras, the relationship between “different” quantum deformations are given in mathoverflow.net/questions/55647/…
Apr 12, 2012 at 5:01 history edited tzhang CC BY-SA 3.0
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Apr 11, 2012 at 20:33 comment added Christopher Drupieski @Allen, I think the isomorphism occurs when your coefficient ring is a power series ring in the indeterminate $q$. If your coefficient ring is only $\mathbb{C}[q]$, or if $q$ is specialized to a complex value, then there is no reason to expect an algebra isomorphism.
Apr 11, 2012 at 20:10 comment added Jim Humphreys @Allen: I'm confused. How would you construct an algebra isomorphism here? @tzhang: What meaning do you attach to the symbol q here? It's used in more than one sense in the literature, sometimes as an indeterminate or arbitrary complex number or root of unity. Does it matter for your question?
Apr 11, 2012 at 17:15 answer added Jake timeline score: 5
Apr 11, 2012 at 16:55 comment added Allen Knutson Aren't $U(\mathfrak g)$ and $U_q(\mathfrak g)$ isomorphic as algebras, only different as coalgebras?
Apr 11, 2012 at 15:57 history edited tzhang CC BY-SA 3.0
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Apr 11, 2012 at 15:51 history asked tzhang CC BY-SA 3.0