10h
comment Boolean simplification of $(ABC)' + (AB)'C + A'BC' +A (BC)' + AB'C$?
Did you look at any of the other dozen problems in the Related Questions thing to the right? Nearly all of them have worked solutions, and I'm pretty sure you would figure out how to proceed if you read those.
10h
comment In a finite ring, if $xy=1$, show $yx=1$.
@litterboy Thanks! I'm sure you'll be writing great posts here in no time. Don't hesitate to ask for help.
14h
revised In a finite ring, if $xy=1$, show $yx=1$.
better title, added a tag
14h
comment In a finite ring, if $xy=1$, show $yx=1$.
@litterboy Also, choose a more descriptive title, and do NOT type in all caps. This has been considered bad netiquette for decades.
14h
comment In a finite ring, if $xy=1$, show $yx=1$.
@litterboy Also, in the future, please search for your question first. I realize this one might not be easy to find, but it is just general advice :) Also, you will get better responses if you include your thoughts so far on the question. If people think you are just posting problems without any effort on your part, you might get a negative response. Good luck!
1d
revised What ring-sum of vector spaces can possibly mean?
edited tags
1d
comment Where does the proof for commutative rings break down in the non-commutative ring when showing only two ideals implies the ring is a field?
Doh: it looks like you read the title without reading the post. My question is: where does the proof for commutative rings break down in the non-commutative ring?
1d
comment Where does the proof for commutative rings break down in the non-commutative ring when showing only two ideals implies the ring is a field?
@yoyo And those are just the Artinian simple rings. There are much nastier simple rings out there.
1d
revised Example of ideals such that $I^n=0$ but $I^{n-1}\not= 0$
added 211 characters in body
1d
comment Example of ideals such that $I^n=0$ but $I^{n-1}\not= 0$
This is pretty much optimal (and could even be applied to a quotient of $\Bbb Z$ so as to try to match the OP's original thinking.
1d
answered Example of ideals such that $I^n=0$ but $I^{n-1}\not= 0$
1d
comment Prove that an ideal is not maximal
When using this argument, wouldn't it just be easier to say "$\Bbb Z[x]/(x)\cong \Bbb Z$ which is clearly not a field."?
1d
answered MCS meet all prime ideals
2d
revised Where does the proof for commutative rings break down in the non-commutative ring when showing only two ideals implies the ring is a field?
better title, tweak grammar
2d
awarded  Constituent
2d
comment A big challenge on Number theory
Here's a big hint: effort shown draws a lot of positive attention and help. Attention grubbing font changes usually do the opposite.
2d
reviewed Approve A big challenge on Number theory
2d
comment To find the two dimensional subspace of $R^{3}$
@godonichia As previously suggested, the right thing to look at is additive closure.
2d
comment To find the two dimensional subspace of $R^{3}$
@godonichia If $V$ is any subspace, $V$ and $\{(0,0)\}$ only share the origin, and yet their union is a subspace. So you're not really adequately explaining why the union of subspaces that don't contain each other is not a subspace.
2d
comment To find the two dimensional subspace of $R^{3}$
@godonichia That's correct...