arXiv subjects

K. Arun Kumar

Publications and source records attributed to K. Arun Kumar.

4 recordsLinked to original sources

arXiv2024

A cellular absolute motivic ring spectrum representing Hermitian K-theory

In the Morel-Voevodsky motivic stable homotopy category of a quasi-compact quasi-separated scheme S, several candidates exist for a motivic spectrum representing hermitian K-theory. This note shows that the cellular absolute motivic spectrum constructed in the thesis of the first author via the geometry of orthogonal and hyperbolic Grassmannians over any scheme coincides with the motivic ring spectrum constructed recently by Calm\`es, Harpaz, and Nardin.

math.KT↗

arXiv2023

Endomorphisms of Equivariant Algebraic $K$-theory

We prove that for the action of a finite constant group scheme, equivariant algebraic $K$-theory is represented by a colimit of Grassmannians in the equivariant motivic homotopy category. Using this result we show that the set of endomorphisms of the equivariant motivic space defined by $K_0(G,-)$ coincides with the set of endomorphisms of infinite Grassmannians in the equivariant motivic homotopy category by explicitly computing the equivariant $K$-theory of Grassmannians.

math.AG↗

arXiv2023

Construction of the motivic cellular spectrum $\mathbf{KO}^{geo}$ over $Spec(\mathbb{Z})$

We construct a periodic motivic spectrum over $Spec(\mathbb{Z})$ which when pulled back to any scheme $S$ with $\frac{1}{2}\in\Gamma(S,\mathcal{O}_S)$ is the $HP^1-$spectrum constructed by Panin and Walter. This spectrum $\mathbf{KO}^{geo}$ is constructed using closed subschemes of the Grassmannians $Gr(r,n)$. Using this we show that $\mathbf{KO}^{geo}$ is cellular.

math.AG↗

arXiv2000

Solitary coherent structures in viscoelastic shear flow: computation and mechanism

Starting from stationary bifurcations in Couette-Dean flow, we compute nontrivial stationary solutions in inertialess viscoelastic circular Couette flow. These solutions are strongly localized vortex pairs, exist at arbitrarily large wavelengths, and show hysteresis in the Weissenberg number, similar to experimentally observed ``diwhirl'' patterns. Based on the computed velocity and stress fields, we elucidate a heuristic, fully nonlinear mechanism for these flows. We propose that these localized, fully nonlinear structures comprise fundamental building blocks for complex spatiotemporal dynamics in the flow of elastic liquids.

physics.flu-dyn↗