MathOverflow

Miles Reid proved that isolated compound du Val singularities are precisely Gorenstein terminal singularities.
Does this hold in positive characteristic setting?Are there any know result?

Let $z$ denote a unit vector.Fix a finite collection of positive semidefinite matrices $\mathcal{P}$.Define the function and set$$f_{\mathcal{P}}(X) = \sum_{P \in \mathcal{P}} z^T X(PX + I)^{-1} z, \quad \mbox{and} \quad \mathcal{X} = \{X \succeq 0,...

René Thom in 1952 proved the formula$$Sq^i(U_2)=\Phi_2(w_i),$$which in modern parlance says that the Steenrod squares of the mod $2$ Thom class of an orthogonal bundle are the images under the mod $2$ Thom isomorphism of the Stiefel-Whitney classes.
Apparently there is a mod $p$ analogue of this formula for oriented bundles, in which the $Sq^i$ are replaced by Steenrod powers $P^i_p$ and the $w_i$ are replaced by polynomials in the Pontryagin classes. Thom refers to this in his famous paper 195...

Let $G$ be a finite doubly transitive group in its action on the set $X$, such that a point stabilizer $G_x$ ($x \in X$) has an abelian normal subgroup $N_x$.
I have read that if $\vert N_x \vert$ is even and $N_x$ acts semi-regularly on $X \setminus \{ x \}$ (Hering, 1972), or if $N_x$ does not act semi-regularly on $X \setminus \{ x \}$ (O'Nan, 1975), such permutation groups are classified without CFSG....