R. N. SenR. N. Sen was a Professor in the Department of Mathematics at Ben-Gurion University, Beer-Sheva, Israel, and is now retired. His main research interests were the theory of symmetry of infinite quantum-mechanical systems and mathematical investigation into the relation between mathematics and physics, particularly the origins of the differentiable structure of space-time. He has taught a broad spectrum of courses on physics and mathematics, as well as demography. A life member of Clare Hall, Cambridge, he has been a Gauss Professor in Göttingen and is also a member of the International Association for Mathematical Physics and the Israel Mathematical Union. Read More Read Less