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Preliminaries 2. A class of perverse sheaves on Ev, Q 3. Multiplication 4. Restriction 5. Fourier-Deligne transform 6. Analysis of a sink 7. Multiplicative generators 8. Compatibility of multiplication with restriction 9. Rank 2 10.Definition of the canonical basis B of U-11.Properties of the canonical basis B of U-12.The variety Av 13.Singular supports 14.Example: graphs of type A, D, E 15. Example: graphs of affine type A 16. Graphs with a cyclic group action
G. Lusztig (Tue,) studied this question.