45-XX	Integral equations
45-00	General reference works (handbooks, dictionaries, bibliographies, etc.)
45-01	Instructional exposition (textbooks, tutorial papers, etc.)
45-02	Research exposition (monographs, survey articles)
45-03	Historical {!must also be assigned at least one classification number from section 01}
45-04	Explicit machine computation and programs (not the theory of computation or programming)
45-06	Proceedings, conferences, collections, etc.
45A05	Linear integral equations
45B05	Fredholm integral equations
45C05	Eigenvalue problems [See also 34Lxx, 35Pxx, 45P05, 47A75]
45D05	Volterra integral equations [See also 34A12]
45Exx	Singular integral equations [See also 30Exx, 44-XX, 30E20, 30E25, 44A15, 44A35]
45E05	Integral equations with kernels of Cauchy type [See also 35J15]
45E10	Integral equations of the convolution type (Abel, Picard, Toeplitz and Wiener - Hopf type) [See also 47B35]
45E99	None of the above, but in this section
45Fxx	Systems of linear integral equations
45F05	Systems of nonsingular linear integral equations
45F10	Dual, triple, etc., integral and series equations
45F15	Systems of singular linear integral equations
45F99	None of the above, but in this section
45Gxx	Nonlinear integral equations [See also 47H30, 47Jxx]
45G05	Singular nonlinear integral equations
45G10	Other nonlinear integral equations
45G15	Systems of nonlinear integral equations
45H05	Miscellaneous special kernels [See also 44A15]
45J05	Integro-ordinary differential equations [See also 34K05, 34K30, 47G20]
45K05	Integro-partial differential equations [See also 34K30, 35R10, 47G20]
45L05	Theoretical approximation of solutions {For numerical analysis, see 65Rxx}
45Mxx	Qualitative behavior
45M05	Asymptotics
45M10	Stability theory
45M15	Periodic solutions
45M20	Positive solutions
45M99	None of the above, but in this section
45N05	Abstract integral equations, integral equations in abstract spaces
45P05	Integral operators [See also 47B38, 47G10]
45Q05	Inverse problems
45R05	Random integral equations [See also 60H20]