Truncation (InstanceTopic, 3)
From Hi.gher. Space
Truncation is the process of cutting polytope facets to produce new polytopes. The kind of truncation can be specified by a Dx number.
Particular types of truncation include:
- Mesotruncation
- Truncates the polytope to its "midpoint". In odd dimensions, this is represented as the middle Coxeter-Dynkin node ringed. In even dimensions, the middle two nodes are ringed.
- Extratruncation
- "Expands" the polytope. This is represented with the first and last nodes ringed. Etymology: "extra" is Latin for "outside" - you can imagine the ringed nodes as being on the "outside" (at the ends) of the diagram.