The Pilgerschritt (Liedl) transform

Abstract

The Pilgerschritt transform was introduced by Roman Liedl, Innsbruck, in the late seventies of the last century. He came up with the idea for this transform after studies of the Volterra product integral and dealing with questions in iteration theory. This paper will show up the main ideas, the achieved results, a lot of open problems and some closely related ideas which followed later on.

Keywords

• product
• integral
• pilgerschritt transform
• one parameter groups
• homomorphism
• lie groups
• geodesic lines