Areas not falling into the Math Subject Classification

Some topics don't seem to fit into just one category of the Mathematics Subject Classification scheme. This page will be a home for them, although right now it's just sort of garbage file. If you know what you're looking for but couldn't find any good matches in the Layman's Guide, try scanning this file for some keywords that seem appropriate for your needs.

There are some areas of mathematics (?) which fall outside the MSC altogether; it's unclear what to offer as a good site for these. For example, one might mention

The sphere FAQ and (division) ring FAQ written some time ago do not seem to fit so neatly into these area boundaries, but we have tried to give them appropriate cross-links as well.

There are some topics which are discussed in several areas of the MSC. We try in such cases to provide crosslinks. See for example the division of material on polynomials, mentioned in the page for 12F: Galois theory.

It looks like there should be multi-heading pages for some parts of mathematics with greatly overlapping resources. For the most part these seem to coincide with the broad-area classifications the AMS used in the MSC until 1972 (see below for defunct MSC codes):

There are many closely allied pairs of fields, too: Probability(60)/Statistics(62), Logic(03)/Set Theory(04), Geometry(51)/Convex Geometry(52), etc.; but pairs of pages are probably easily crosslinked, that is, there's probably no need to set up "parent" pages for these pairs.

There are some subjects which, based on reports in the popular press and the presentations in the undergraduate curriculum, one might expect to be major portions of the subject classification system. Did you look for these in vain? Here are a few pointers:

There are some topics which just aren't mathematics! It's always possible, perhaps, that a person lands at this web site completely by mistake. What non-mathematical query might have brought you here?:

Perhaps it's also appropriate to show the nearest cognates with other classification systems. e.g. Computing Reviews? AIP? See the page for 00-XX. [Computing reviews:]

One might envision other ways to break up the discipline and see how even they are. Sample topics: distribution of SIAM members' fields of interest; distribution of Fields medalists; division of math fields in AMS's annual list of recent PhDs; etc.

What about the defunct parts of the MSC? A few fields were discarded after a reorganization: 02 (became 03), 10 (became 11), 21 (became 22), 50 (became 51); A few fields were for papers unclassifiable except for broad field: 09(algebra), 27(analysis), 36 (differential equations), 48(geometry), 56(topology), 69(applied math), 99(misc). Some numbers were apparently never used: 7,23-25,29,37-38, 59,61,63-64,66-67,74-75,77,87-89,95-98

For more detail on old classifications, see URL:

09 (40-72) Classical algebra

         09-XX (40-72) Classical algebra
             09.0X (40-58) Algebra
             09.00 (59-72) Classical algebra
             09.1X (40-58) Abstract algebra
             09.2X (40-58) Elementary algebra
             09.3X (40-58) Rings, fields and algebras

21 (40-58) Topological algebraic structures

         21-XX (40-58) Topological algebraic structures
             21.0X (40-58) Topological algebraic structures

27 (40-58) Analysis

         27-XX (40-58) Analysis
             27.0X (40-58) Analysis
             27.1X (40-58) Foundations of analysis
             27.2X (40-58) Theory of sets, theory of functions of
            real variables
             27.3X (40-58) Theory of functions of real variables,
            theory of measure and integration
             27.4X (40-58) Geometrical analysis
             27.5X (40-58) Functions with particular properties

36 (40-58) Differential equations, operational calculus

         36-XX (40-58) Differential equations, operational
             36.0X (40-58) Differential equations
             36.1X (40-58) Differential equations, operational

48 (40-58) Geometry

         48-XX (40-58) Geometry
             48.0X (40-58) Geometry

56 (40-58) Topology

         56-XX (40-58) Topology
             56.0X (40-58) Topology

69 (40-72) General applied mathematics

         69-XX (40-72) General applied mathematics
             69.00 (59-79) General Applied Mathematics

71 (40-58) Mechanics

        71-XX (1940-1958) Mechanics
            71.0X (1940-1958) Mechanics

79 (40-58) Mathematical physics, physical applications

        79-XX (1940-1958) Mathematical physics, physical
            79.0X (1940-1958) Mathematical physics, physical

84 (40-58) Relativity, astronomy

        84-XX (1940-1958) Relativity, astronomy
            84.0X (1940-1958) Relativity, astronomy

91 (40-58) Other applications

        91-XX (1940-1958) Other applications
            91.0X (1940-1958) Other applications

99 (40-58) Miscellaneous

         99-XX (40-58) Miscellaneous
            99.0X (40-58) Miscellaneous

Like we said, this is still sort of a garbage file...

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Last modified 1999/06/12 by Dave Rusin. Mail: