The induced transformation on a properly chosen interval of a 2-interval exchange
transformation is a 2-interval exchange transformation again. This induction is
explicitly integrated by using the simple continued fraction algorithm.
Therefore, we can say that the simple continued fraction algorithm acts well as
a ‘‘multiplicative Rauzy induction’’ on the family of 2-interval exchange
transformations. Now, we have the following question; On what kind of family of
3-interval exchange transformations does the negative slope algorithm act well
as a multiplicative Rauzy induction? The purpose of this paper is to give the
answer to this question.