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:
“The note of the white-throated sparrow, a very inspiriting but almost wiry sound, was first heard in the morning, and with this all the woods rang. This was the prevailing bird in the northern part of Maine. The forest generally was alive with them at this season, and they were proportionally numerous and musical about Bangor. They evidently breed in that State.”
—Henry David Thoreau (1817–1862)