13XX 


Commutative algebra 

13Axx 

General commutative ring theory 


13A02 
Graded rings [See also 16W50] 


13A05 
Divisibility; factorizations [See also 13F15] 


13A15 
Ideals; multiplicative ideal theory 


13A18 
Valuations and their generalizations [See also 12J20] 


13A30 
Associated graded rings of ideals (Rees ring, form ring), analytic spread and related topics 


13A35 
Characteristic $p$ methods (Frobenius endomorphism) and reduction to characteristic $p$; tight closure [See also 13B22] 


13A50 
Actions of groups on commutative rings; invariant theory [See also 14L24] 


13A99 
None of the above, but in this section 