You need to know: Euclidean space , notation
for the set of positive integers. In addition, you need to know the concept of Hausdorff dimension of set
to understand the “moreover” part of the Theorem.
Background: For , let
denote the distance from x to the nearest integer. Let
be the set of
such that
and
. Given
, we say that point
is
-badly approximable if there exists
such that
for all
, with convention that
. Let Bad(r) be be set of all
-badly approximable points in
.
The Theorem: On 2nd April 2013, Victor Beresnevich submitted to arxiv a paper in which he proved that for any finite subset , the set
is non-empty. Moreover, this set has Hausdorff dimension n.
Short context: A real number x is said to be badly approximable if there exists a constant such that
for all
. Sets Bad(r) are natural generalisations containing n-tuples
of simultaneously badly approximable numbers. In 1983, Schmidt conjectured that
. In 2011, Badziahin, Pollington, and Velani proved the
case of the Theorem, which implies the Schmidt’s conjecture as a special case. The Theorem is a generalisation of this result to all dimensions.
Links: Free arxiv version of the original paper is here, journal version is here.