Page 1 of 1

Tests for subgroups and subrings

Posted: Wed Nov 04, 2009 5:39 am
by mtey
I thought you may find these useful.

http://en.wikipedia.org/wiki/Subgroup_test

http://en.wikipedia.org/wiki/Subring_test

They are fairly easy and if you memorize these tests you will have no trouble finding whether a particular subset is subring or subgroup. Pay attention that the subring test here does not require a ring to have a unity!