It might be a stupid question. How to glue perverse sheaves? I am considering the following example. Flag variety of $sl_2$, which is $P^1$. Consider category of perverse sheaves on $P^1$. Denoted by $Perv(P^1)$. The big cells of flag variety of $sl_2$ give the affine cover for it. In this case, they should be two $A^1$. We can also consider category of perverse sheaves on $A^1$. My question is: 1. How to glue two pieces of perverse sheaves on 1-dimensional affine spaces to that of projective spaces? More general, is there any gluing machinery which can globalize the perverse sheaves? It seems that Beilinson had a paper talking about this, but what I preferred is some expository notes explaining with some examples. 2. Maybe I need to ask this in another question. How can one define perverse sheaves on noncommutative space. I am aware that there is a paper by Amnon Yekutieli, James J. Zhang talking about [perverse sheaves on noncommutative space][1]. However, what they considered was not really a noncommutative space from my understanding.(If I made mistake or bullshit, point out please). They consider quasi coherent sheaves of (not necessarily)commutative algebra on commutative scheme. Which does not fit my need. I am considering the following example: Quantized flag variety of $sl_2$ i.e. $Proj(O_q(G/N))$ in the sense of [Lunts-Rosenberg][2](see also [Erik Backelin and Kobi Kremnitzer][3] and [Tanisaki][4]). It is a noncommutative scheme. I wonder whether James Zhang has also defined dualizing complexes for this case. **How to define category of perverse sheaves on quantized flag variety** ? The motivation for this question is I think there should be **quantum version of Riemann-Hilbert correspondence**. Which should describe the categorical equivalence: $Perv(Proj(O_q(G/N))$ and category of quantum holonomic D-modules on quantized flag variety. At present, I have more interest to know the answer of question 1. Thank you! [1]: http://arxiv.org/abs/math/0211309 [2]: http://www.springerlink.com/content/xp7xvqu6ahncmf4v/ [3]: http://arxiv.org/PS_cache/math/pdf/0401/0401108v2.pdf [4]: http://arxiv.org/abs/math/0309349