MathOverflow

In D. Halpern-Leistner’s paper The Derived Category of a GIT Quotient and other places of the literature, it is claimed that from the main theorem of the paper one can reconstruct Beilinson’s exceptional collection for $D^b(\mathbb{P}^n)$. However, I...

Is there a degree-5 polynomial $ p\left(t\right) = a_0 + a_1 \cdot t + a_2 \cdot t^2 + a_3 \cdot t^3 + a_4 \cdot t^4 + a_5 \cdot t^5 $ with integer coefficients $ a_j $, such that $ p\left(t\right) $ is irreducible over rationals, but the second iterate...

To prove the multilinear-restriction theorem as follows:
The argument is through multilinear-kekeya inequality and other common tools, as follows
I have a question about local orthogonality. There are two local orthogonalities in the proof, one is for $B_{R^{1/2}}$, the other is for $B_R$ region. But my understanding is that $\theta$ here are $R^{-1/2}$-caps of $\Sigma_j$. In this case, the local...

I am trying to understand the characterization of the class of closed embeddings into a normal Hausdorff space as the class of continuous maps satisfying the left lifting property with respect to a unique map, presented in https://ncatlab.org/nlab/show...