Published online by Cambridge University Press: 25 April 2022
We prove that for any prime power
$q\notin \{3,4,5\}$
, the cubic extension
$\mathbb {F}_{q^{3}}$
of the finite field
$\mathbb {F}_{q}$
contains a primitive element
$\xi $
such that
$\xi +\xi ^{-1}$
is also primitive, and
$\operatorname {\mathrm {Tr}}_{\mathbb {F}_{q^{3}}/\mathbb {F}_{q}}(\xi )=a$
for any prescribed
$a\in \mathbb {F}_{q}$
. This completes the proof of a conjecture of Gupta et al. [‘Primitive element pairs with one prescribed trace over a finite field’, Finite Fields Appl. 54 (2018), 1–14] concerning the analogous problem over an extension of arbitrary degree
$n\ge 3$
.
T. Trudgian was supported by Australian Research Council Future Fellowship FT160100094.