# Varieties and pure symbols

**Authors:** Alexander Vishik

arXiv: 2509.00592 · 2025-09-03

## TL;DR

This paper demonstrates that the 2-isotropy of projective varieties is governed by pure symbols in Milnor K-theory, linking geometric properties with algebraic invariants and field extension equivalences.

## Contribution

It establishes a novel connection between 2-isotropy, Milnor K-theory symbols, and algebraic cycle equivalences in projective varieties.

## Key findings

- 2-isotropy is controlled by pure symbols in Milnor K-theory
- Pure symbols determine 2-equivalence of field extensions
- Pure symbols influence numerical equivalence of algebraic cycles

## Abstract

In this article, we prove that the 2-isotropy of any projective variety is controlled by a pure symbol in the Milnor's K-theory (mod 2) of the flexible closure of the base field. We also show that such pure symbols control the 2-equivalence of field extensions as well as the numerical equivalence of algebraic cycles (with mod 2 coefficients).

## Full text

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## References

12 references — full list in the complete paper: https://tomesphere.com/paper/2509.00592/full.md

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Source: https://tomesphere.com/paper/2509.00592