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Koszul Duality and Geometric Satake for SL 2 ( R ) Oliver Straser - PowerPoint PPT Presentation

Koszul Duality Geometric Satake Connecting both pictures Geometric Tensoration Koszul Duality and Geometric Satake for SL 2 ( R ) Oliver Straser Annual conference of the DFG priority programme in representation theory, SPP 1388 March 27, 2013


  1. Koszul Duality Geometric Satake Connecting both pictures Geometric Tensoration Koszul Duality and Geometric Satake for SL 2 ( R ) Oliver Straser Annual conference of the DFG priority programme in representation theory, SPP 1388 March 27, 2013 Oliver Straser Koszul Duality and Geometric Satake for SL 2( R )

  2. Koszul Duality Geometric Satake Connecting both pictures Geometric Tensoration Motivation G = PSL 2 ( C ), ˇ g := sl 2 ( R ) ⊗ C and K = SO 2 ( R ) Oliver Straser Koszul Duality and Geometric Satake for SL 2( R )

  3. Koszul Duality Geometric Satake Connecting both pictures Geometric Tensoration Motivation G = PSL 2 ( C ), ˇ g := sl 2 ( R ) ⊗ C and K = SO 2 ( R ) H C := { (ˇ g , K )-modules of finite length } with integral infinitisimal character Oliver Straser Koszul Duality and Geometric Satake for SL 2( R )

  4. Koszul Duality Geometric Satake Connecting both pictures Geometric Tensoration Motivation G = PSL 2 ( C ), ˇ g := sl 2 ( R ) ⊗ C and K = SO 2 ( R ) H C := { (ˇ g , K )-modules of finite length } with integral infinitisimal character X Adams-Barbasch-Vogan parameter space of G . (will be defined later) Oliver Straser Koszul Duality and Geometric Satake for SL 2( R )

  5. � Koszul Duality Geometric Satake Connecting both pictures Geometric Tensoration Motivation G = PSL 2 ( C ), ˇ g := sl 2 ( R ) ⊗ C and K = SO 2 ( R ) H C := { (ˇ g , K )-modules of finite length } with integral infinitisimal character X Adams-Barbasch-Vogan parameter space of G . (will be defined later) Koszul Duality roughly identifies: D b G ( X ) H C Oliver Straser Koszul Duality and Geometric Satake for SL 2( R )

  6. � � Koszul Duality Geometric Satake Connecting both pictures Geometric Tensoration G = PSL 2 ( C ), ˇ g := Lie SL 2 ( C ) and K = SO 2 ( R ) H C := { (ˇ g , K )-modules of finite length } with integral infinitisimal character X Adams-Barbasch-Vogan parameter space of G . (will be defined later) Koszul Duality roughly identifies: D b H C G ( X ) F ⊗ F finite dimensional SL 2 ( C ) representation. Oliver Straser Koszul Duality and Geometric Satake for SL 2( R )

  7. � � � Koszul Duality Geometric Satake Connecting both pictures Geometric Tensoration G = PSL 2 ( C ), ˇ g := Lie SL 2 ( C ) and K = SO 2 ( R ) H C := { (ˇ g , K )-modules of finite length } with integral infinitisimal character X Adams-Barbasch-Vogan parameter space of G . (will be defined later) Koszul Duality roughly identifies: D b G ( X ) H C F ⊗ ? F finite dimensional SL 2 ( C ) representation. Oliver Straser Koszul Duality and Geometric Satake for SL 2( R )

  8. � � � Koszul Duality Geometric Satake Connecting both pictures Geometric Tensoration G = PSL 2 ( C ), ˇ g := Lie SL 2 ( C ) and K = SO 2 ( R ) H C := { (ˇ g , K )-modules of finite length } with integral infinitisimal character X Adams-Barbasch-Vogan parameter space of G . (will be defined later) Koszul Duality roughly identifies: D b G ( X ) H C F ⊗ ? F finite dimensional SL 2 ( C ) representation. Question Is there a nice (geometric) desciption of “?” Oliver Straser Koszul Duality and Geometric Satake for SL 2( R )

  9. Koszul Duality Geometric Satake Connecting both pictures Geometric Tensoration Outline Koszul Duality 1 Geometric Satake 2 Connecting both pictures 3 Geometric Tensoration 4 Oliver Straser Koszul Duality and Geometric Satake for SL 2( R )

  10. Koszul Duality Geometric Satake Connecting both pictures Geometric Tensoration Some Notation G = PSL 2 ( C ), fix a Borel B and a maximal torus T ⊂ B determining a system of pos. roots. Oliver Straser Koszul Duality and Geometric Satake for SL 2( R )

  11. Koszul Duality Geometric Satake Connecting both pictures Geometric Tensoration Some Notation G = PSL 2 ( C ), fix a Borel B and a maximal torus T ⊂ B determining a system of pos. roots. g ⊃ ˇ ˇ h cartanian. Via the Harish-Chandra isomorphism we indentify the set of integral infinitisimal characters with N 0 g } ∼ h ∗ / W ⊃ N 0 ρ ∼ = ˇ { Inf. Chars. of ˇ = N 0 Oliver Straser Koszul Duality and Geometric Satake for SL 2( R )

  12. Koszul Duality Geometric Satake Connecting both pictures Geometric Tensoration Some Notation G = PSL 2 ( C ), fix a Borel B and a maximal torus T ⊂ B determining a system of pos. roots. g ⊃ ˇ ˇ h cartanian. Via the Harish-Chandra isomorphism we indentify the set of integral infinitisimal characters with N 0 g } ∼ h ∗ / W ⊃ N 0 ρ ∼ = ˇ { Inf. Chars. of ˇ = N 0 For any infinitisimal character n ∈ N 0 H C n = { M ∈ H C | ( n ( z ) − z ) k M = 0 for k ≫ 0 and ∀ z ∈ Z ( U (ˇ g )) } and the category of Harish-Chandra Modules with integral infinitisimal character H C = ⊕ n ∈ N 0 H C n is stable under tensoring with finite dimensional SL 2 ( C ) representations. Oliver Straser Koszul Duality and Geometric Satake for SL 2( R )

  13. Koszul Duality Geometric Satake Connecting both pictures Geometric Tensoration Some More Notation Let X be a complex variety (equipped with the analytic topology) acted upon by some linear algebraic group G , then D b G ( X ) denotes the Bernstein-Lunts equivariant derived category. Oliver Straser Koszul Duality and Geometric Satake for SL 2( R )

  14. Koszul Duality Geometric Satake Connecting both pictures Geometric Tensoration Some More Notation Let X be a complex variety (equipped with the analytic topology) acted upon by some linear algebraic group G , then D b G ( X ) denotes the Bernstein-Lunts equivariant derived category. If the G -orbits on X are of finite number then these orbits define a stratification of X . Oliver Straser Koszul Duality and Geometric Satake for SL 2( R )

  15. Koszul Duality Geometric Satake Connecting both pictures Geometric Tensoration Some More Notation Let X be a complex variety (equipped with the analytic topology) acted upon by some linear algebraic group G , then D b G ( X ) denotes the Bernstein-Lunts equivariant derived category. If the G -orbits on X are of finite number then these orbits define a stratification of X . The category of equivariant perverse sheaves Perv G ( X ) is artinian. (i.e. abelian and every object has finite length) Oliver Straser Koszul Duality and Geometric Satake for SL 2( R )

  16. Koszul Duality Geometric Satake Connecting both pictures Geometric Tensoration Some More Notation Let X be a complex variety (equipped with the analytic topology) acted upon by some linear algebraic group G , then D b G ( X ) denotes the Bernstein-Lunts equivariant derived category. If the G -orbits on X are of finite number then these orbits define a stratification of X . The category of equivariant perverse sheaves Perv G ( X ) is artinian. (i.e. abelian and every object has finite length) Let D ss G ( X ) full additive subcategory of semisimple objects of D b G ( X ). (An object in D b G ( X ) is called semisimple if it is isomorphic to finte direct sum of shifted simple objects of Perv G ( X )) Oliver Straser Koszul Duality and Geometric Satake for SL 2( R )

  17. Koszul Duality Geometric Satake Connecting both pictures Geometric Tensoration Geometric Parameter Spaces Definition (Adams-Barbasch-Vogan) Let Y := { g ∈ G | g 2 = 1 } , Oliver Straser Koszul Duality and Geometric Satake for SL 2( R )

  18. Koszul Duality Geometric Satake Connecting both pictures Geometric Tensoration Geometric Parameter Spaces Definition (Adams-Barbasch-Vogan) Let Y := { g ∈ G | g 2 = 1 } , � G × B Y if n > 0 X ( n ) := Y if n = 0 is called the Geometric Parameter Space for n ∈ N 0 . Oliver Straser Koszul Duality and Geometric Satake for SL 2( R )

  19. Koszul Duality Geometric Satake Connecting both pictures Geometric Tensoration Geometric Parameter Spaces Definition (Adams-Barbasch-Vogan) Let Y := { g ∈ G | g 2 = 1 } , � G × B Y if n > 0 X ( n ) := Y if n = 0 is called the Geometric Parameter Space for n ∈ N 0 . Theorem (Soergel, 02) For any n ∈ N 0 there exists an graded Version H C Z n of H C n Oliver Straser Koszul Duality and Geometric Satake for SL 2( R )

  20. Koszul Duality Geometric Satake Connecting both pictures Geometric Tensoration Geometric Parameter Spaces Definition (Adams-Barbasch-Vogan) Let Y := { g ∈ G | g 2 = 1 } , � G × B Y if n > 0 X ( n ) := Y if n = 0 is called the Geometric Parameter Space for n ∈ N 0 . Theorem (Soergel, 02) For any n ∈ N 0 there exists an graded Version H C Z n of H C n such that n ∼ P H C Z = D ss G ( X ( n )) Oliver Straser Koszul Duality and Geometric Satake for SL 2( R )

  21. Koszul Duality Geometric Satake Connecting both pictures Geometric Tensoration Affine Grassmannians K = C ( ( t ) ) O := C [ [ t ] ] Oliver Straser Koszul Duality and Geometric Satake for SL 2( R )

  22. Koszul Duality Geometric Satake Connecting both pictures Geometric Tensoration Affine Grassmannians K = C ( ( t ) ) O := C [ [ t ] ] G ( K ) and G ( O ) Oliver Straser Koszul Duality and Geometric Satake for SL 2( R )

  23. Koszul Duality Geometric Satake Connecting both pictures Geometric Tensoration Affine Grassmannians K = C ( ( t ) ) O := C [ [ t ] ] G ( K ) and G ( O ) � t − n � 0 t n := ( t → ) ∈ hom( C × , T ) ⊂ G ( K ) 0 1 Oliver Straser Koszul Duality and Geometric Satake for SL 2( R )

  24. Koszul Duality Geometric Satake Connecting both pictures Geometric Tensoration Affine Grassmannians K = C ( ( t ) ) O := C [ [ t ] ] G ( K ) and G ( O ) � t − n � 0 t n := ( t → ) ∈ hom( C × , T ) ⊂ G ( K ) 0 1 G ( K ) n := G ( O ) t n G ( O ) Oliver Straser Koszul Duality and Geometric Satake for SL 2( R )

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