Classes in Hpmn+1(F) of lower exponent
Abstract
Let $F$ be a field of characteristic $p>0$. We prove that if a symbol $A=ω\otimes β_1 \otimes \dots \otimes β_n$ in $H_{p^m}^{n+1}(F)$ is of exponent dividing $p^{m-1}$, then its symbol length in $H_{p^{m-1}}^{n+1}(F)$ is at most $p^n$. In the case $n=2$ we also prove that if $A= ω_1\otimes β_1+\cdots+ω_r\otimes β_r$ in $H_{p^{m}}^2(F)$ satisfies $\exp(A)|p^{m-1}$, then the symbol length of $A$ in $H_{p^{m-1}}^2(F)$ is at most $p^r+r-1$. We conclude by looking at the case $p=2$ and proving that if $A$ is a sum of two symbols in $H_{2^m}^{n+1}(F)$ and $\exp A |2^{m-1}$, then the symbol length of $A$ in $H_{2^{m-1}}^{n+1}(F)$ is at most $(2n+1)2^n$. Our results use norm conditions in characteristic $p$ in the same manner as Matrzi in his paper ``On the symbol length of symbols''.
Fields of Study & Subjects
Coding theory and cryptography
Publication details
- Journal / source
- Annals of K-Theory
- Volume
- 11
- Issue
- 1
- Pages
- 37–46
- Publication date
- 31 January 2026
- Language
- EN