  Computational reductions are an important and powerful concept in computer
science. However, they are difficult for many students to grasp. In this paper,
we outline a concept for how the learning of reductions can be supported by
educational support systems. We present an implementation of the concept within
such a system, concrete web-based and interactive learning material for
reductions, and report on our experiences using the material in a large
introductory course on theoretical computer science.
