Teaching the reduction technique with interactive visualizations: report on a simple automatic tutor

The reduction technique is an important problem solving method
often used in computer science and mathematics to solve a new problem by
the known solution of another problem.
In this paper we investigate the potential of interactive
visualization for teaching the reduction method and
focus on the following two questions:
What part can visualizations play in the presentation and understanding of
the reduction technique? and:
How can we build systems for teaching the reduction technique
that can be used by students in a teleteaching environment?
We try to answer the latter question by reporting on a field
test of an automatic tutor which we have build for our students.