# Etale Steenrod operations and the Artin-Tate pairing

## TL;DR

This paper proves Tate's 1966 conjecture that the Artin-Tate pairing on the Brauer group of a surface over a finite field is always alternating, using étale Steenrod operations and characteristic classes.

## Contribution

It establishes the alternating property of the Artin-Tate pairing by connecting it to étale Steenrod operations, a novel approach inspired by algebraic topology.

## Key findings

- Confirmed the pairing is always alternating
- Developed methods to compute étale Steenrod operations
- Linked algebraic geometry with topological tools

## Abstract

We prove a 1966 conjecture of Tate concerning the Artin-Tate pairing on the Brauer group of a surface over a finite field, which is the analogue of the Cassels-Tate pairing. Tate asked if this pairing is always alternating and we find an affirmative answer, which is somewhat surprising in view of the work of Poonen-Stoll on the Cassels-Tate pairing. Our method is based on studying a connection between the Artin-Tate pairing and (generalizations of) Steenrod operations in \'{e}tale cohomology. Inspired by an analogy to the algebraic topology of manifolds, we develop tools allowing us to calculate the relevant \'{e}tale Steenrod operations in terms of characteristic classes.