Let X be a Poisson variety with a Hamiltonian G-action and H be a normal subgroup of G. Then X//G is obtained by a (Hamiltonian) reduction of X//H by the induced G/H-action under suitable assumptions, called reduction by stages. We apply for the Slodowy slices and show that the Slodowy slice associated to (𝔀,π’ͺ) is obtained by a reduction of the Slodowy slice associated to (𝔀,π’ͺ’) for a simple Lie algebra 𝔀 and nilpotent orbits π’ͺ, π’ͺ’ such that π’ͺ > π’ͺ’ with some conditions. The quantum cases imply that the finite/affine W-algebras associated to (𝔀,π’ͺ) are obtained by W-algebras associated to (𝔀,π’ͺ’), which proves a conjecture of Morgan in finite cases and gives a conjectural generalization of results of Madsen and Ragoucy in affine cases.

This is a joint work with Thibault Juillard.

This video was produced by the International Centre for Mathematical Sciences, as part of the workshop Geometric Representation Theory and W-algebras.