Published online by Cambridge University Press: 20 November 2018
Suppose that $G$ is an abelian group,
$A\,\subset \,G$ is finite with
$\left| A\,+\,A \right|\,\le \,K\left| A \right|$ and
$\eta \,\in \,(0,\,1]$ is a parameter. Our main result is that there is a set
$L$ such that
$$\left| A\,\cap \,\text{Span}\left( L \right) \right|\ge {{K}^{-{{O}_{n}}\left( 1 \right)}}\left| A \right|\,\,\,\,\text{and}\,\,\,\,\,\left| L \right|=O\left( {{K}^{n}}\log \left| A \right| \right).$$
We include an application of this result to a generalisation of the Roth-Meshulam theorem due to Liu and Spencer