Preface |
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vii | |
Introduction |
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ix | |
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Perverse sheaves and the topology of algebraic varieties |
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1 | (58) |
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Lecture 1 The decomposition theorem |
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3 | (14) |
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1.1 Deligne's theorem in cohomology |
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3 | (1) |
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1.2 The global invariant cycle theorem |
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4 | (1) |
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1.3 Cohomological decomposition theorem |
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5 | (1) |
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1.4 The local invariant cycle theorem |
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6 | (1) |
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7 | (1) |
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1.6 The decomposition theorem |
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8 | (2) |
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1.7 Exercises for Lecture 1 |
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10 | (7) |
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Lecture 2 The category of perverse sheaves P(Y) |
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17 | (11) |
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2.1 Three "Whys", and a brief history of perverse sheaves |
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17 | (2) |
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2.2 The constructible derived category D (Y) |
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19 | (2) |
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2.3 Definition of perverse sheaves |
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21 | (1) |
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2.4 Artin vanishing and Lefschetz hyperplane theorems |
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22 | (2) |
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2.5 The perverse t-structure |
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24 | (1) |
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2.6 Intersection complexes |
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25 | (1) |
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2.7 Exercises for Lecture 2 |
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26 | (2) |
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Lecture 3 Semi-small maps |
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28 | (9) |
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29 | (2) |
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3.2 The decomposition theorem for semi-small maps |
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31 | (1) |
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3.3 Hilbert schemes of points on surfaces and Heisenberg algebras |
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31 | (2) |
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3.4 The endomorphism algebra End(f*Qx) |
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33 | (1) |
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3.5 Geometric realization of the representations of the Weyl group |
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34 | (1) |
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3.6 Exercises for Lecture 3 |
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35 | (2) |
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Lecture 4 Symmetries: VD, RHL, Jc splits off |
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37 | (9) |
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4.1 Verdier duality and the decomposition theorem |
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37 | (1) |
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4.2 Verdier duality and the decomposition theorem with large fibers |
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38 | (1) |
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4.3 The relative hard Lefschetz theorem |
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39 | (1) |
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4.4 Application of RHL: Stanley's theorem |
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40 | (1) |
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4.5 Intersection cohomology of the target as a direct summand |
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41 | (2) |
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4.6 Pure Hodge structure on intersection cohomology groups |
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43 | (1) |
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4.7 Exercises for Lecture 4 |
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44 | (2) |
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Lecture 5 The perverse filtration |
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46 | (10) |
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5.1 The perverse spectral sequence and the perverse filtration |
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47 | (1) |
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5.2 Geometric description of the perverse filtration |
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48 | (2) |
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5.3 Hodge-theoretic consequences |
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50 | (1) |
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5.4 Character variety and Higgs moduli: P = W |
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50 | (3) |
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5.5 Let us conclude with a motivic question |
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53 | (1) |
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5.6 Exercises for Lecture 5 |
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54 | (2) |
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56 | (3) |
An introduction to affine Grassmannians and the geometric Satake equivalence |
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59 | (96) |
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Abstract. We introduce various affine Grassmannian varieties, study their geometric properties, and give some applications. We also discuss the geometric Satake equivalence. These are the expanded lecture notes for a mini-course in the 2015 PCMI summer school. |
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60 | (6) |
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60 | (1) |
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61 | (2) |
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0.3 Conventions and notations |
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63 | (3) |
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66 | (1) |
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Lecture 1 Affine Grassmannians and their first properties |
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66 | (15) |
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1.1 The affine Grassmannian of GLn |
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66 | (2) |
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1.2 Affine Grassmannians of general groups |
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68 | (3) |
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1.3 Groups attached to the punctured disc |
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71 | (3) |
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1.4 The Beauville-Laszlo theorem |
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74 | (2) |
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1.5 The determinant line bundle |
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76 | (3) |
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1.6 Affine Grassmannians over the complex numbers |
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79 | (1) |
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1.7 Affine Grassmannians for p-adic groups |
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80 | (1) |
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Lecture 2 More on the geometry of affine Grassmannians |
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81 | (15) |
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81 | (6) |
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2.2 Digression: Some sub-ind-schemes in Gr |
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87 | (1) |
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2.3 Opposite Schubert "varieties" and transversal slices |
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88 | (4) |
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92 | (2) |
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2.5 Central extensions and affine Kac-Moody algebras |
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94 | (2) |
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Lecture 3 Beilinson-Drinfeld Grassmannians and factorisation structures |
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96 | (12) |
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3.1 Beilinson-Drinfeld Grassmannians |
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96 | (7) |
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3.2 Factorisation property |
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103 | (1) |
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104 | (1) |
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3.4 Rigidified line bundles on GrRan |
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105 | (3) |
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Lecture 4 Applications to the moduli of G-bundles |
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108 | (8) |
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4.1 One point uniformization |
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108 | (2) |
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4.2 Line bundles and conformal blocks |
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110 | (1) |
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4.3 Adelic uniformization |
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111 | (5) |
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Lecture 5 The geometric Satake equivalence |
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116 | (29) |
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5.1 The Satake category Sate |
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117 | (2) |
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5.2 Sate as a Tannakian category |
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119 | (3) |
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122 | (8) |
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130 | (4) |
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134 | (8) |
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5.6 From the geometric Satake to the classical Satake |
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142 | (3) |
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A Complements on sheaf theory |
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145 | (11) |
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A.1 Equivariant category of perverse sheaves |
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145 | (4) |
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A.2 Universally local acyclicity |
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149 | (6) |
Lectures on Springer theories and orbital integrals |
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155 | (96) |
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Abstract. These are the expanded lecture notes from the author's mini-course during the graduate summer school of the Park City Math Institute in 2015. The main topics covered are: geometry of Springer fibers, affine Springer fibers and Hitchin fibers; representations of (affine) Weyl groups arising from these objects; relation between affine Springer fibers and orbital integrals. |
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156 | (1) |
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0.1 Topics of these notes |
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156 | (1) |
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0.2 What we assume from the reader |
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157 | (1) |
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Lecture 1 Springer fibers |
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157 | (13) |
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157 | (1) |
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158 | (1) |
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1.3 Examples of Springer fibers |
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159 | (3) |
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1.4 Geometric Properties of Springer fibers |
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162 | (1) |
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1.5 The Springer correspondence |
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163 | (4) |
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1.6 Comments and generalizations |
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167 | (1) |
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168 | (2) |
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Lecture 2 Affine Springer fibers |
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170 | (20) |
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2.1 Loop group, parahoric subgroups and the affine flag variety |
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170 | (4) |
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2.2 Affine Springer fibers |
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174 | (2) |
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2.3 Symmetry on affine Springer fibers |
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176 | (2) |
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2.4 Further examples of affine Springer fibers |
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178 | (3) |
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2.5 Geometric Properties of affine Springer fibers |
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181 | (5) |
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2.6 Affine Springer representations |
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186 | (2) |
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2.7 Comments and generalizations |
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188 | (1) |
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189 | (1) |
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Lecture 3 Orbital integrals |
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190 | (13) |
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3.1 Integration on a p-adic group |
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190 | (1) |
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191 | (3) |
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3.3 Relation with affine Springer fibers |
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194 | (1) |
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3.4 Stable orbital integrals |
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195 | (3) |
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198 | (3) |
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3.6 Remarks on the Fundamental Lemma |
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201 | (1) |
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202 | (1) |
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Lecture 4 Hitchin fibration |
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203 | (49) |
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4.1 The Hitchin moduli stack |
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204 | (2) |
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206 | (2) |
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208 | (2) |
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4.4 Relation with affine Springer fibers |
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210 | (2) |
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4.5 A global version of the Springer action |
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212 | (1) |
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213 | (38) |
Lectures on K-theoretic computations in enumerative geometry |
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251 | (130) |
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252 | (11) |
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1.1 K-theoretic enumerative geometry |
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252 | (2) |
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1.2 Quantum K-theory of Nakajima varieties |
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254 | (3) |
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1.3 K-theoretic Donaldson-Thomas theory |
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257 | (4) |
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261 | (1) |
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262 | (1) |
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Lecture 2 Before we begin |
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263 | (10) |
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2.1 Symmetric and exterior algebras |
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263 | (3) |
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266 | (3) |
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269 | (3) |
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272 | (1) |
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Lecture 3 The Hilbert scheme of points of 3-folds |
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273 | (25) |
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3.1 Our very first DT moduli space |
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273 | (2) |
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275 | (4) |
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279 | (5) |
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3.4 Tangent bundle and localization |
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284 | (7) |
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3.5 Proof of Nekrasov's formula |
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291 | (7) |
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Lecture 4 Nakajima varieties |
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298 | (6) |
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4.1 Algebraic symplectic reduction |
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298 | (1) |
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4.2 Nakajima quiver varieties [ 35,61,62] |
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299 | (2) |
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4.3 Quasimaps to Nakajima varieties |
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301 | (3) |
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Lecture 5 Symmetric powers |
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304 | (10) |
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5.1 PT theory for smooth curves |
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304 | (4) |
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5.2 Proof of Theorem 5.1.16 |
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308 | (2) |
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5.3 Hilbert schemes of surfaces and threefolds |
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310 | (4) |
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Lecture 6 More on quasimaps |
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314 | (21) |
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6.1 Balanced classes and square roots |
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314 | (3) |
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6.2 Relative quasimaps in an example |
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317 | (5) |
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6.3 Stable reduction for relative quasimaps |
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322 | (5) |
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6.4 Moduli of relative quasimaps |
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327 | (4) |
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6.5 The degeneration formula and the gluing operator |
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331 | (4) |
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335 | (11) |
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335 | (3) |
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338 | (3) |
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341 | (1) |
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342 | (1) |
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7.5 Large framing vanishing |
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343 | (3) |
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Lecture 8 Difference equations |
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346 | (9) |
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8.1 Shifts of Kahler variables |
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346 | (2) |
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8.2 Shifts of equivariant variables |
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348 | (4) |
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8.3 Difference equations for vertices |
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352 | (3) |
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Lecture 9 Stable envelopes and quantum groups |
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355 | (12) |
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9.1 K-theoretic stable envelopes |
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355 | (4) |
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9.2 Triangle lemma and braid relations |
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359 | (5) |
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9.3 Actions of quantum groups |
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364 | (3) |
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Lecture 10 Quantum Knizhnik-Zamolodchikov equations |
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367 | (14) |
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10.1 Commuting difference operators from R-matrices |
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367 | (2) |
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10.2 Minuscule shifts and qKZ |
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369 | (3) |
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10.3 The gluing operator in the stable basis |
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372 | (2) |
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10.4 Proof of Theorem 10.2.11 |
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374 | (7) |
Lectures on perverse sheaves on instanton moduli spaces |
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381 | |
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381 | (6) |
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Lecture 2 Uhlenbeck partial compactification - in brief |
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387 | (3) |
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Lecture 3 Heisenberg algebra action on the Gieseker partial compactification |
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390 | (7) |
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Lecture 4 Stable envelopes |
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397 | (9) |
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Lecture 5 Sheaf theoretic analysis of stable envelopes |
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406 | (8) |
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Lecture 6 R-matrix for Gieseker partial compactification |
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414 | (6) |
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Lecture 7 Perverse sheaves on instanton moduli spaces |
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420 | (8) |
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Lecture 8 W-algebra representation on circle plusd IHT(UdG) |
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428 | (3) |
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Lecture 9 Concluding remarks |
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431 | |