Special Session 13: 

On the construction of the natural extensions of the nearest integer complex continued fraction maps

Rie Natsui
Japan Women`s University
Japan
Co-Author(s):    
Abstract:
We consider the nearest integer complex continued fraction map associated to the Euclidean fields $\mathbb Q(\sqrt{-d})$, $d = 1, 2, 3, 7, 11$. For each map, we see that there is an absolutely continuous ergodic invariant probability measure. We will explain how to construct the natural extension of each map on a subset of $\mathbb C \times \mathbb C$. Then the invariant measure for this extension is derived from the hyperbolic measure on $\mathbb H^{3}$ and the density function of the absolutely continuous invariant measure is given as its marginal.