Title: Stable Basis and Quantum Cohomology of Cotangent Bundles of Flag Varieties
Description: The stable envelope for symplectic resolutions, constructed by Maulik and Okounkov, is a key ingredient in their work on quantum cohomology and quantum K-theory of Nakajima quiver varieties. In this thesis, we study the various aspects of the cohomological stable basis for the cotangent bundle of flag varieties. We compute its localizations, use it to calculate the quantum cohomology of the cotangent bundles, and relate it to the Chern--Schwartz--MacPherson class of Schubert cells in the flag variety.