# Diagonal forms of higher degree over function fields of $p$-adic curves

## TL;DR

This paper studies diagonal forms of higher degree over function fields of p-adic curves, showing isotropy over certain fields when isotropic over completions, and relates this to bounds on the higher u-invariant.

## Contribution

It introduces a method to analyze isotropy of diagonal forms over specific fields using patching, extending understanding of higher u-invariants for these forms.

## Key findings

- Isotropic forms over completions imply isotropy over related fields.
- The work complements existing bounds on the higher u-invariant.
- Focus on diagonal forms of degree d in characteristic not dividing d!.

## Abstract

We investigate diagonal forms of degree $d$ over the function field $F$ of a smooth projective $p$-adic curve: if a form is isotropic over the completion of $F$ with respect to each discrete valuation of $F$, then it is isotropic over certain fields $F_U$, $F_P$ and $F_p$. These fields appear naturally when applying the methodology of patching; $F$ is the inverse limit of the finite inverse system of fields $\{F_U,F_P,F_p\}$. Our observations complement some known bounds on the higher $u$-invariant of diagonal forms of degree $d$. We only consider diagonal forms of degree $d$ over fields of characteristic not dividing $d!$.