Chu Space
A Chu space is a binary relation from a Set 
to an antiset 
which is defined as a Set which transforms via converse functions.
References
Stanford Concurrency Group. ``Guide to Papers on Chu Spaces.'' http://boole.stanford.edu/chuguide.html.
- Regular Local Ring
- Regular Number
- Regular Parameterization
- Regular Patch
- Regular Point
- Regular Polygon
- Regular Polyhedron
- Regular Prime
- Regular Ring
- Regular Sequence
- Regular Singularity
- Regular Singular Point
- Regular Surface
- Regular Triangle Center
- Regulus
- Reidemeister Moves
- Reidemeister's Theorem
- Reinhardt Domain
- Relation
- Relative Error
- Relative Extremum
- Relatively Prime
- Relative Maximum
- Relative Minimum
- Relaxation Methods