let R be a commutative ring and fix a in R. Show that I_a = {x in R | ax=0} is an ideal of R.

Printable View

- Apr 5th 2009, 12:05 PMCoda202Ideals of Rings
let R be a commutative ring and fix a in R. Show that I_a = {x in R | ax=0} is an ideal of R.

- Apr 5th 2009, 12:41 PMclic-clac
Hi

Do you know the definition of an ideal? Which part can't you prove (additive subgroup, closed under multiplication) ?

Don't forget $\displaystyle R$ commutativity.