Rudolf Ahlswede — From 60 to 66

On September 15th, 2004 Rudolf Ahlswede celebrated his 66th birthday and we describe here developments in his work in the last six years. For an account on the first 60 years we refer to the preface of the book “Numbers, Information and Complexity”, special volume in honour of R. Ahlswede on occasion of his 60th birthday, edited by Ingo Althöfer, Ning Cai, Gunter Dueck, Levon Khachatrian, Mark S. Pinsker, Andras Sárközy, Ingo Wegener and Zhen Zhang, Kluwer Academic Publishers, Boston, Dordrecht, London, 2000. From there we just cite the following paragraph describing Ahlswede’s approach to Information Theory:

”Ahlswede’s path to Information Theory, where he has been world-wide a leader for several decades, is probably unique, because it went without any engineering background through Philosophy: Between knowing and not knowing there are several degrees of knowledge with probability, which can even quantitatively be measured – unheard of in classical Philosophy.

During the period to be described here came on January 30, 2002 as a shock the message of the sudden and unexpected passing of his collaborator and friend Levon Khachatrian. His untimely death disrupted a very fruitful cooperation. We refer the reader to the memorial text on Levon Khachatrian in this volume for an appreciation of person and work.