A Note On Terminology
Older terminology referred to limits as "inverse limits" or "projective limits," and to colimits as "direct limits" or "inductive limits." This has been the source of a lot of confusion.
There are several ways to remember the modern terminology. First of all,
- cokernels,
- coequalizers, and
- codomains
are types of colimits, whereas
- kernels,
- equalizers, and
- domains
are types of limits. Second, the prefix "co" implies "first variable of the ". Terms like "cohomology" and "cofibration" all have a slightly stronger association with the first variable, i.e., the contravariant variable, of the bifunctor.
Read more about this topic: Limit (category Theory)
Famous quotes containing the word note:
“However intense my experience, I am conscious of the presence and criticism of a part of me, which, as it were, is not a part of me, but a spectator, sharing no experience, but taking note of it, and that is no more I than it is you. When the play, it may be the tragedy, of life is over, the spectator goes his way. It was a kind of fiction, a work of the imagination only, so far as he was concerned.”
—Henry David Thoreau (1817–1862)