Shai Keidar

activity

20192026

collaborators

6 papers

math.CT2026

The Gray Product of $(\infty, n)$ -Categories via Lax Grids

Shai Keidar, Leor Neuhauser

We introduce a new model for $(\infty, n)$ -categories as Segal sheaves on lax grids, which are pasting diagrams of lax cubes. This model allows for a direct construction of the Gray…

math.CT2025

Cofinality via Weighted Colimits

Shai Keidar, Lior Yanovski

We prove a refinement of Quillen's Theorem A, providing necessary and sufficient conditions for a functor to be cofinal with respect to diagrams valued in a fixed $\infty$ -category…

math.AT2025

Semiadditive Alternating Powers and Twisted Power Operation

Shai Keidar, Shaul Ragimov

We study a class of representations of symmetric groups in higher semiadditive categories. For these representations in $Mod_{E_{n}}^{\land}$ , the transchromatic character…

math.AT2025

Twisted Graded Categories

Shai Keidar, Shaul Ragimov

Given a presentably symmetric monoidal $\infty$ -category $C$ and an $E_{\infty}$ -monoid $M$ , we introduce and classify twisted graded categories, which generaliz…

math.AT2024

On The Telescopic Picard Group

Shai Keidar

We prove that for any prime $p$ and height $n \geq 1$ , the telescopic Picard group $Pic (Sp_{T n})$ contains a subgroup of the form $\mathbb{Z}_p \times \mathbb{Z}/a…

math.RT2019

$P gl_{2}$ is Multiplicity-Free as a $P G L_{2} \times P G L_{2}$ -Variety

Dmitry Gourevitch, Shai Keidar

Let $F$ be a non-Archimedean local field. Let $G$ be an algebraic group over $F$ . A $G$ -variety $X$ defined over $F$ is said to be multiplicity-free if for any admissible irreducib…