Pace P. Nielsen

activity

20042025

most citedOdd Perfect Numbers Have At Least Nine Distinct Prime Factors

17 citations · 56 across the 8 of their papers we have counts for

collaborators

Showing 2015Show all

2 papers · 1 filter

math.RA2015

Connections between unit-regularity, regularity, cleanness, and strong cleanness of elements and rings

Pace P. Nielsen, Janez Šter

We construct an example of a unit-regular ring which is not strongly clean, answering an open question of Nicholson. We also characterize clean matrices with a zero column, and thi…

math.CO2015★ 3 cited

On Vaughan Pratt's crossword problem

George M. Bergman, Pace P. Nielsen

Vaughan Pratt has introduced objects consisting of pairs $(A, W)$ where $A$ is a set and $W$ a set of subsets of $A,$ such that (i) $W$ contains $\emptyset$ and $A,$ (ii) if $C$ is…