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, term-rewriting)
• 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}
• 16S40 Smash products of general Hopf actions, See also {16W30}
• 16S50 Endomorphism rings: matrix rings, See also {15-XX}
• 16S60 Rings of functions, subdirect products, sheaves of rings
• 16S70 Extensions of rings by ideals
• 16S80 Deformations of rings, See also {14D15}
• 16S90 Maximal ring of quotients, 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