35XX PARTIAL DIFFERENTIAL EQUATIONS
 3500 General reference works (handbooks, dictionaries, bibliographies, etc.)
 3501 Instructional exposition (textbooks, tutorial papers, etc.)
 3502 Research exposition (monographs, survey articles)
 3503 Historical (must also be assigned at least one classification number from Section 01)
 3504 Explicit machine computation and programs (not the theory of computation or programming)
 3506 Proceedings, conferences, collections, etc.

35Axx General topics
(1)
 35Bxx Qualitative properties of solutions
 35Cxx Representations of solutions
 35Dxx Generalized solutions

35Exx Equations and systems with constant coefficients [See also 35N05]
(1)
 35Fxx General firstorder equations and systems
 35Gxx General higherorder equations and systems
 35Hxx Closetoelliptic equations and systems
 35Jxx Elliptic equations and systems [See also 58J10, 58J20]
 35Kxx Parabolic equations and systems [See also 35Bxx, 35Dxx, 35R30, 35R35, 58J35]
 35Lxx Hyperbolic equations and systems [See also 58J45]
 35Mxx Equations and systems of special type (mixed, composite, etc.)
 35Nxx Overdetermined systems [See also 58Hxx, 58J10, 58J15]
 35Pxx Spectral theory and eigenvalue problems [See also 47Axx, 47Bxx, 47F05]

35Qxx Equations of mathematical physics and other areas of application [See also 35J05, 35J10, 35K05, 35L05]
(2)
 35Rxx Miscellaneous topics (For equations on manifolds, see 58Jxx; for manifolds of solutions, see 58Bxx; for stochastic PDE, see also 60H15)
 35Sxx Pseudodifferential operators and other generalizations of partial differential operators [See also 47G30, 58J40]