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Aug 29, 2012 at 14:11 vote accept Réamonn Ó Buachalla
Aug 18, 2012 at 17:49 answer added anonymous timeline score: 2
Jul 22, 2012 at 14:43 history edited Réamonn Ó Buachalla CC BY-SA 3.0
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Jul 22, 2012 at 9:47 comment added Réamonn Ó Buachalla To clarify: For the reasons MTS gave, I am most interested in the surjective case, certainly not injective.
Jul 22, 2012 at 6:27 comment added user22479 @MTS: Thanks for clarifying, sorry for my initial confusion.
Jul 22, 2012 at 3:19 comment added MTS Interesting question - I guess I've only really thought about examples that were faithfully flat, so I don't have one off the top of my head. I will think about it.
Jul 22, 2012 at 2:54 comment added MTS No, I meant to ask if the map was surjective. In that case one would regard $H$ as a "quantum subgroup" of $G$, and the algebra $M$ is a coideal subalgebra of $G$. If $G$ was the function algebra of a group, and $H$ the function algebra of the subgroup, $\pi$ would be the restriction map, and $M$ would be the subalgebra of functions invariant under translation by the subgroup, i.e. the function algebra of the corresponding homogeneous space; hence the term "quantum homogeneous space."
Jul 22, 2012 at 2:09 comment added user22479 @MTS: Despite the "G" and "H" notation, they are rings and not "geometric" objects, so the map $\pi$ is analogous in the algebraic geometry setting to the map between coordinate rings rather than their spectra. So rather than ask if $\pi$ is surjective, you probably meant to ask if it is assumed to be injective (for which the answer is probably "yes"...which the OP can confirm or not).
Jul 22, 2012 at 1:50 comment added Réamonn Ó Buachalla No. I would even be interested in cases where $\pi$ is just a bialgebra map.
Jul 22, 2012 at 1:38 comment added MTS Do you require $\pi$ to be surjective?
Jul 22, 2012 at 0:26 history asked Réamonn Ó Buachalla CC BY-SA 3.0