[Math] Canonical examples of algebraic structures

ac.commutative-algebrabig-listexamplesgr.group-theoryra.rings-and-algebras

Please list some examples of common examples of algebraic structures. I was thinking answers of the following form.

"When I read about a [insert structure here], I immediately think of [example]."

Or maybe you think about a small number of examples. For example, when someone says "group", maybe you immediately think of one example of an abelian group and one example of a non-abelian group. Maybe you have a list of examples that you test new theorems on.

I am an analyst by training. When I read algebra, I can follow the logic line by line, but I don't have the repertoire of examples in my head that I have for analysis and so it's hard for me to picture anything.

Best Answer

Neat question...

Abelian Group: Z or Z/nZ

Nonabelian Group: Dihedral groups or GL_n

Commutative Ring: Z or C[x]

Noncommutative Ring: Matrix rings

Division Ring: Hamilton's Quaternions

Field: R or C

Lie Algebra: sl_2