Immeasurable rotope (no ontology)

From Higher Dimensions Database

An immeasurable rotope is a rotope which has a superscript letter inside a group in its group notation definition.

The effect of this is that the orientation of a non-spherical part of a group in the rotope is undefined, making it impossible to calculate hypervolumes which depend on this orientation.

The lowest-dimensional immeasurable rotope is the three-dimensional triangular torus.