Death of Professor Magnus

The purpose of death: a reply to Professor Dworkin.

Magnus Jiborn

A classical problem in political theory is how to explain unpopular and oppressive minority rule. How can a small minority manage to dominate a much larger population against its will? How come the oppressed majority does not revolt? Two rival approaches can be distinguished: the coordination theory, according to which the power of the minority rests on coordinated action among the minority and...

ND professor predicts little change in policies with Andropov’s death

The death o f Soviet leader Yuri V. A ndropov has left the w orld w ondering what changes his succes­ sor w ill bring. D irector o f Soviet Studies at N otre Dame, G eorge Brinkley, told The Observer, “1 don’t think his death will have m uch effect at all. The issues are bigger than one man and the Soviet leadership is m ore than one man.” In a statem ent issued by the W hite H ouse staff, Pres...

Convergence of the Magnus Series

The Magnus series is an infinite series which arises in the study of linear ordinary differential equations. If the series converges, then the matrix exponential of the sum equals the fundamental solution of the differential equation. The question considered in this paper is: When does the series converge? The main result establishes a necessary condition for convergence, which improves on seve...

Magnus expansions and beyond

In this brief review we describe the coming of age of Magnus expansions as an asymptotic and numerical tool in the investigation of linear differential equations in a Lie-group and homogeneous-space setting. Special attention is afforded to the many connections between modern theory of geometric numerical integration and other parts of mathematics: from abstract algebra to differential geometry...