40-XX	Sequences, series, summability
40-00	General reference works (handbooks, dictionaries, bibliographies, etc.)
40-01	Instructional exposition (textbooks, tutorial papers, etc.)
40-02	Research exposition (monographs, survey articles)
40-03	Historical {!must also be assigned at least one classification number from section 01}
40-04	Explicit machine computation and programs (not the theory of computation or programming)
40-06	Proceedings, conferences, collections, etc.
40Axx	Convergence and divergence of infinite limiting processes
40A05	Convergence and divergence of series and sequences
40A10	Convergence and divergence of integrals
40A15	Convergence and divergence of continued fractions [See also 30B70]
40A20	Convergence and divergence of infinite products
40A25	Approximation to limiting values (summation of series, etc.) {For the Euler - Maclaurin summation formula, see 65B15}
40A30	Convergence and divergence of series and sequences of functions
40A99	None of the above, but in this section
40B05	Multiple sequences and series {!should also be assigned at least one other classification number in this section}
40Cxx	General summability methods
40C05	Matrix methods
40C10	Integral methods
40C15	Function-theoretic methods (including power series methods and semicontinuous methods)
40C99	None of the above, but in this section
40Dxx	Direct theorems on summability
40D05	General theorems
40D09	Structure of summability fields
40D10	Tauberian constants and oscillation limits
40D15	Convergence factors and summability factors
40D20	Summability and bounded fields of methods
40D25	Inclusion and equivalence theorems
40D99	None of the above, but in this section
40Exx	Inversion theorems
40E05	Tauberian theorems, general
40E10	Growth estimates
40E15	Lacunary inversion theorems
40E20	Tauberian constants
40E99	None of the above, but in this section
40F05	Absolute and strong summability
40Gxx	Special methods of summability
40G05	Ces\`aro, Euler, N\"orlund and Hausdorff methods
40G10	Abel, Borel and power series methods
40G99	None of the above, but in this section
40H05	Functional analytic methods in summability
40J05	Summability in abstract structures [See also 43A55, 46A35, 46B15]