### Abstract:

I'll discuss some problems that have bothered me for a while on small sums of roots of unity, on covering congruences, and on semi-magic squares. Among the questions I may discuss are:How small can a nonzero sum of five nnth roots of unity be?

1. How small can a nonzero sum of five nnth roots of unity be?
2. Can Z⊕ZZ⊕Z be written as a finite, disjoint union of cosets of distinct, proper subgroups?
3. What's the smallest'' 4×44×4 matrix with natural number entries and all row and column sums equal that can't be written as an integer linear combination of nine permutation matrices?
Speaker

Gerry Myerson

Research Area
Affiliation

Macquarie

Date

Wed, 24/02/2016 - 2:30pm

Venue

RC-2063, The Red Centre, UNSW