On Mawhin's approach to multiple nonabsolutely convergent integral
On the 1/2 Problem of Besicovitch: quasi-arcs do not contain sharp saw-teeth.
In this paper we give an alternative proof of our recent result that totally unrectifiable 1-sets which satisfy a measure-theoretic flatness condition at almost every point and sufficiently small scales, satisfy Besicovitch's 1/2-Conjecture which states that the lower spherical density for totally unrectifiable 1-sets should be bounded above by 1/2 at almost every point. This is in contrast to rectifiable 1-sets which actually possess a density equal to unity at almost every point. Our present method...
On the fundamental group of the fixed points of an unipotent action.