On the dependence of the affine Springer fibers on their root valuation datum

For the group ${\mathrm{G}\mathrm{L}}_d$, we confirm a conjecture of Goresky, Kottwitz and MacPherson, which states that the cohomology of the affine Springer fibers depend only on the root valuation datum of their defining elements. The proof relies on a microlocal analysis of the intermediate extensions appearing in Ngô’s support theorem, and a Whitney regularity property of the union of the strict $\delta$-strata over the equisingular strata for the miniversal deformation of plane curve singularities.