The math archive was introduced on Dec 1 1997 with the following announcement:
We are introducing the math archive. The idea is to facilitate growth to areas of mathematics not covered by the current archive structure. The math archive has the same features as the current archives (searching, subscribing, web downloading and so on) with one important addition: Authors must include a Subj-class header, chosen from a canonical list. This is most easily done with a select menu for web submission, but the header can alternatively be included in e-mail submissions; see our abstract preparation help. You may subscribe to any subset of classifications; see our math subscription help. In this sense, each subject class functions as a new archive. This also makes it very easy to expand the archive by adding new subject classifications. [12/97]
Note: It is no longer possible to make submissions via e-mail. For more information about submissions, see our submission help page.
Constructive comments are solicited concerning the proper subject classes. (See below for why we are not using directly the Math Subject Classification used by Math Reviews and Zentralblatt für Mathematik.) The current list has been created by a committee of interested mathematicians and is available at the math archive page.
(The old archives alg-geom, dg-ga, funct-an, and q-alg have been included as subject classifications. Old papers will be available as always, but new papers will be routed automatically to the math archive with the appropriate Subj-class. In October 2002 the subject classifications "LA - Linear Algebra" an "SC - Scientific Computation" were discontinued and folded into "RA - Rings and Algebras" and "NA - Numerical Analysis" respectively. In May 2004 the subject classification "PR - Probability Theory" was split into "PR - Probability" and "ST - Statistics". In July 2007 the subject classification "IT - Information Theory" was made an alias for "IT - Information Theory" in the cs archive.)
The categories (or subject classes) of the xxx math archive bear some resemblance to the top-level sections of the Math Subject Classification (MSC) used by Math Reviews and Zentrallblatt für Mathematik. The two classifications, however, differ in their intent and history, and the math archive advisory committee decided that strictly following the MSC was unworkable. For example, Quantum Algebra, the most popular category in the math archive, has no counterpart in the MSC. It would be impractical, perhaps even counterproductive, to reorganize this category into MSC sections. Each category of the math archive must maintain a self-sustaining stream of new submissions in order to be useful; the committee decided that the MSC sections are in places too specific or too dated for this purpose.
Finally, all authors are encouraged as well to use the optional MSC-class: field when submitting new e-prints, since some readers may wish to search for e-prints by their MSC classification.
Important areas may have been overlooked and the best names may not have been chosen. These oversights can be corrected. Please contact arXiv administrators with any comments.
The advisory committee members serve as consultants to Cornell University and to the arXiv scientific advisory board. All arXiv policy decisions are ultimately made by Cornell University.