ScalingStacks

Proof. The motivic extension algebra $E$ can be identified with $R_{\mathbf{d}}.$ To see this, one can adapt the proof of Varagnolo–Vasserot [VV11, Theorem 3.6] from the context of equivariant Borel–Moore homology to Chow groups. Their arguments apply unchanged making use of the fact that the partial quiver flag varieties admit affine pavings and hence their equivariant Borel–Moore homology and Chow groups coindice. By Proposition 6.1 conditions (PT) and (PO) hold and the statement follows by Theorem 4.9. ∎