A solution to an open problem of Cassels and Diophantine properties of cubic numbers.

Seminar: 
Group Actions and Dynamics
Event time: 
Monday, March 2, 2009 - 11:30am to 12:30pm
Location: 
431 DL
Speaker: 
Uri Shapira
Speaker affiliation: 
Hebrew University Jerusalem
Event description: 

We prove existence of real numbers x,y, possessing
the following property:

For any real $a,b,$ $ \liminf |n| ||nx - a|| ||ny - b|| = 0$,
where $||c|| $ denotes the distance of c to the nearest integer.

This answers a 50 years old question of Cassels.
The most interesting part of the result is that there are algebraic
numbers with the above property!