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ON THE PRODUCT OF ELEMENTS WITH PRESCRIBED TRACE

Published online by Cambridge University Press:  14 May 2020

JOHN SHEEKEY
Affiliation:
University College Dublin, School of Mathematics and Statistics, Science Centre, East Belfield, Dublin 4, Ireland email: john.sheekey@ucd.ie
GEERTRUI VAN DE VOORDE
Affiliation:
School of Mathematics and Statistics,University of Canterbury, Private Bag 4800,Christchurch 8140, New Zealand email: geertrui.vandevoorde@canterbury.ac.nz
JOSÉ FELIPE VOLOCH*
Affiliation:
School of Mathematics and Statistics,University of Canterbury, Private Bag 4800,Christchurch 8140, New Zealand

Abstract

This paper deals with the following problem. Given a finite extension of fields $\mathbb{L}/\mathbb{K}$ and denoting the trace map from $\mathbb{L}$ to $\mathbb{K}$ by $\text{Tr}$, for which elements $z$ in $\mathbb{L}$, and $a$, $b$ in $\mathbb{K}$, is it possible to write $z$ as a product $xy$, where $x,y\in \mathbb{L}$ with $\text{Tr}(x)=a,\text{Tr}(y)=b$? We solve most of these problems for finite fields, with a complete solution when the degree of the extension is at least 5. We also have results for arbitrary fields and extensions of degrees 2, 3 or 4. We then apply our results to the study of perfect nonlinear functions, semifields, irreducible polynomials with prescribed coefficients, and a problem from finite geometry concerning the existence of certain disjoint linear sets.

Type
Research Article
Copyright
© 2020 Australian Mathematical Publishing Association Inc.

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Footnotes

Communicated by M. Coons

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