When a cube is created in Mondrian, and the dimension has multiple hierarchies does Pentaho viewer allow you to display both? If not how does it choose the one it displays?
yup...click the "open olap navigator" button. Select the dimension with the multiple hierarchies (eg. date dimension). You'll see all hierarchies and you'll be able to select which one jpivot will display. By default, the 1st hierarchy in the mondrian schema is displayed.