Degree one maps of Seifert manifolds and a note on Seifert volume

The existence of degree one maps defines an interesting partial order in the set of geometric 3-manifolds, modulo homotopy equivalences. Here we classify this partial order among aspherical Seifert fibered spaces. We also consider the Seifert volume and show that it has some properties similar to that of Gromovʹs norm under a degree d map.