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Feb 21, 2017 at 4:57 answer added YCor timeline score: 3
May 5, 2010 at 18:43 answer added Jim Humphreys timeline score: 15
May 5, 2010 at 16:47 comment added BCnrd A very nice fact over fields $k$ of char. 0: for any linear algebraic $k$-group G and Lie $k$-subalgebra h in g = Lie(G), [h,h] = Lie(G') for a (unique) connected closed $k$-subgroup $G'$ in $G$. In particular, if h is a semisimple Lie $k$-subalgebra of g (so h = [h,h]) then it is the Lie algebra of a connected closed $k$-subgroup of $G$. See 7.9 in Borel's book on linear algebraic groups (and 7.7 for a nec/sufficient condition in general, in char. 0). So as always, it's the commutative/solvable stuff that creates all the headaches.
May 5, 2010 at 14:51 answer added Allen Knutson timeline score: 8
May 5, 2010 at 6:17 answer added Nicolás timeline score: 0
Oct 21, 2009 at 13:30 answer added JS Milne timeline score: 42
Oct 15, 2009 at 19:25 vote accept Anton Geraschenko
Oct 15, 2009 at 14:38 answer added Enno timeline score: 3
Oct 15, 2009 at 6:28 answer added William Slofstra timeline score: 28
Oct 7, 2009 at 21:17 answer added Theo Johnson-Freyd timeline score: 0
Oct 5, 2009 at 20:02 answer added Ben Webster timeline score: 1
Oct 5, 2009 at 19:48 history asked Anton Geraschenko CC BY-SA 2.5