210 citations · 464 across the 57 of their papers we have counts for
6 papers · 1 filter
High density piecewise syndeticity of sumsets
Mauro Di Nasso, Isaac Goldbring, Renling Jin +3
Renling Jin proved that if A and B are two subsets of the natural numbers with positive Banach density, then A+B is piecewise syndetic. In this paper, we prove that, under various…
Class-preserving automorphisms of universal hyperlinear groups
Martino Lupini
We show that the group of class-preserving automorphisms of a universal hyperlinear group has index 2 inside the group of all automorphisms.
Strongly productive ultrafilters on semigroups
David Fernández Bretón, Martino Lupini
We prove that if S is a commutative semigroup with well founded universal semilattice or a solvable inverse semigroup with well founded semilattice of idempotents, then every stron…
Introduction to Sofic and Hyperlinear groups and Connes' embedding conjecture
Valerio Capraro, Martino Lupini
Sofic and hyperlinear groups are the countable discrete groups that can be approximated in a suitable sense by finite symmetric groups and groups of unitary matrices. These notions…
On a sumset conjecture of Erdős
Mauro Di Nasso, Isaac Goldbring, Renling Jin +3
Erdős conjectured that for any set with positive lower asymptotic density, there are infinite sets such that . We…
Unitary equivalence of automorphisms of separable C*-algebras
Martino Lupini
We prove that the automorphisms of any separable C*-algebra that does not have continuous trace are not classifiable by countable structures up to unitary equivalence. This implies…