Smooth functions with simple structures on 3-dimensional closed manifolds with prescribed Reeb graphs and preimages

Abstract

We give a new answer to so-called realization problems of graphs as Reeb graphs of smooth functions with prescribed preimages of regular values having nice structures. We present a best possible answer for functions on 3-dimensional closed manifolds. The Reeb space of a smooth function is the quotient space of the manifold of the domain induced from the following equivalence relation; two points in the manifold are equivalent if and only if they are points of a same connected component of some preimage. They are in considerable cases graphs (Reeb graphs). Reeb spaces with preimages represent the manifolds well and are important tools in geometry. Recently they play important roles in applications of mathematics such as visualizations. Realization problems ask us whether we can construct smooth functions with prescribed Reeb graphs and preimages. Studies on construction respecting preimages were essentially started by the author.