16XX 


Associative rings and algebras {For the commutative case, see 13XX} 

16Sxx 

Rings and algebras arising under various constructions 


16S10 
Rings determined by universal properties (free algebras, coproducts, adjunction of inverses, etc.) 


16S15 
Finite generation, finite presentability, normal forms (diamond lemma, termrewriting) 


16S20 
Centralizing and normalizing extensions 


16S30 
Universal enveloping algebras of Lie algebras [See mainly 17B35] 


16S32 
Rings of differential operators [See also 13N10, 32C38] 


16S34 
Group rings [See also 20C05, 20C07], Laurent polynomial rings 


16S35 
Twisted and skew group rings, crossed products 


16S36 
Ordinary and skew polynomial rings and semigroup rings [See also 20M25] 


16S37 
Quadratic and Koszul algebras 


16S38 
Rings arising from noncommutative algebraic geometry [See also 14A22] 


16S40 
Smash products of general Hopf actions [See also 16T05] 


16S50 
Endomorphism rings; matrix rings [See also 15XX] 


16S60 
Rings of functions, subdirect products, sheaves of rings 


16S70 
Extensions of rings by ideals 


16S80 
Deformations of rings [See also 13D10, 14D15] 


16S85 
Rings of fractions and localizations [See also 13B30] 


16S90 
Torsion theories; radicals on module categories [See also 13D30, 18E40} {For radicals of rings, see 16Nxx]} 


16S99 
None of the above, but in this section 