Date: Feb 3, 2013 11:46 PM
Author: William Elliot
Subject: Re: Finite Rings
On Sun, 3 Feb 2013, Arturo Magidin wrote:

> On Sunday, February 3, 2013 9:21:19 PM UTC-6, William Elliot wrote:

> > > If R is a finite commutative ring without multiplicative identity

> > > and if every element is a zero divisor, then does there exist

> > > a nonzero element which annihilates all elements of the ring?

> > Ask-an-Algebraist

> > No - the trivial ring.

>

> Incorrect. The trivial ring *does* have a multiplicative identity. I'll let you figure out what it is and why it *does* satisfy the condition that 1x=x=x1 for all x in the ring.

> In fact, I'll give you three guesses.

> The first two don't count, though.

>

Your trivial ring isn't as trivial as my trivial ring because

your trivial ring is fancied up with a multiplicative identity.

> > So add the premise that R has a nonzero element.

> Or, perhaps, not.

Definitely so for OP asked about rings without multiplicative identities.