# Pure Maths Colloquium: Demi Allen

This talk is part of the Pure Maths Colloquium at the University of St Andrews. Check out our upcoming talks at http://theran.lt/pure-colloquium/.

 Where: Lecture Theatre D When: Nov 15 2018 @ 16.00
 Speaker: Demi Allen University of Manchester Title: A general mass transference principle

In Diophantine Approximation we are often interested in the Lebesgue and Hausdorff measures of certain $\limsup$ sets. In 2006, motivated by such considerations, Beresnevich and Velani proved a remarkable result — the Mass Transference Principle — which allows for the transference of Lebesgue measure theoretic statements to Hausdorff measure theoretic statements for $\limsup$ sets arising from sequences of balls in $\mathbb{R}^k$. Subsequently, they extended this Mass Transference Principle to the more general situation in which the $\limsup$ sets arise from sequences of neighbourhoods of “approximating” planes. In this talk, I aim to discuss two recent strengthenings and generalisations of this latter result. Firstly, in a joint work with Victor Beresnevich (York), we have removed some potentially restrictive conditions from the statement given by Beresnevich and Velani. The improvement we obtain yields a number of interesting applications in Diophantine Approximation. Secondly, in a joint work with Simon Baker (Warwick), we have extended these results to a more general class of sets which include smooth manifolds and certain fractal sets.