- commuting elements
- commuting endomorphisms
- commuting extensions
- commuting mappings
- commuting matrices
- commuting operators
- commuting ring
- commuting subgroups
- commuting transformations
- commutor
- comodule
- comodule algebra
- comodule homomorphism
- comonad
- comonotone approximation
- co-Moore space
- comorphism
- formal spectrum
- formal sum
- formal system
- formal theory
- formal training
- formal transformation
- formal undecidable proposition
- formal unsolvability