Maximal Ideal and its relationship with the ring












1














I understand that if $I$ is a maximal ideal of $R$, then $I+xR =R$ $forall x notin I$, but I fail to grasp how the converse can be true. Would anyone be so kind as to offer me a proof/ some hints at how the proof can be done?










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  • That is not true if $x in I$ !
    – barto
    Nov 29 '18 at 12:10






  • 2




    What do you mean exactly with ‘the converse’?
    – Bernard
    Nov 29 '18 at 12:14
















1














I understand that if $I$ is a maximal ideal of $R$, then $I+xR =R$ $forall x notin I$, but I fail to grasp how the converse can be true. Would anyone be so kind as to offer me a proof/ some hints at how the proof can be done?










share|cite|improve this question
























  • That is not true if $x in I$ !
    – barto
    Nov 29 '18 at 12:10






  • 2




    What do you mean exactly with ‘the converse’?
    – Bernard
    Nov 29 '18 at 12:14














1












1








1







I understand that if $I$ is a maximal ideal of $R$, then $I+xR =R$ $forall x notin I$, but I fail to grasp how the converse can be true. Would anyone be so kind as to offer me a proof/ some hints at how the proof can be done?










share|cite|improve this question















I understand that if $I$ is a maximal ideal of $R$, then $I+xR =R$ $forall x notin I$, but I fail to grasp how the converse can be true. Would anyone be so kind as to offer me a proof/ some hints at how the proof can be done?







abstract-algebra ring-theory maximal-and-prime-ideals






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edited Nov 29 '18 at 12:12









MotylaNogaTomkaMazura

6,542917




6,542917










asked Nov 29 '18 at 12:07









hephaes

1729




1729












  • That is not true if $x in I$ !
    – barto
    Nov 29 '18 at 12:10






  • 2




    What do you mean exactly with ‘the converse’?
    – Bernard
    Nov 29 '18 at 12:14


















  • That is not true if $x in I$ !
    – barto
    Nov 29 '18 at 12:10






  • 2




    What do you mean exactly with ‘the converse’?
    – Bernard
    Nov 29 '18 at 12:14
















That is not true if $x in I$ !
– barto
Nov 29 '18 at 12:10




That is not true if $x in I$ !
– barto
Nov 29 '18 at 12:10




2




2




What do you mean exactly with ‘the converse’?
– Bernard
Nov 29 '18 at 12:14




What do you mean exactly with ‘the converse’?
– Bernard
Nov 29 '18 at 12:14










1 Answer
1






active

oldest

votes


















3














The converse is obviously true. Since if $I$ satisfies the condition then $I$ cannot be contained in any proper ideal $J$ of $R$ because if $xin Jsetminus I$ then $R=Rx +Isubseteq J+Isubseteq J+J =J$.






share|cite|improve this answer



















  • 1




    Why the downvote? This is the obvious idea.
    – rschwieb
    Nov 29 '18 at 12:37










  • @rschwieb While this is the answer, I disagree that it is “obviously true” — it was certainly not obvious to the OP.
    – Santana Afton
    Nov 29 '18 at 12:46








  • 2




    +1 This is the very obvious idea, and I agree that it is obviously true.
    – Servaes
    Nov 29 '18 at 13:49












  • @SantanaAfton If you happened to assign a downvote for that reason, I'd just urge you to reconsider, since the sentiment (although you disagree with it) does not affect the correctness, quality or usefulness of the answer. Downvotes simply because one "does not like the way someone says something" are not very helpful to the community. Although, it would be completely natural to leave a comment opining that the answer would be better without the "obviously." :)
    – rschwieb
    Nov 29 '18 at 14:08












  • @rschwieb I voted not because I don’t like the “obvious” sentiment, but because I find such answers as less useful and of lower quality. That said, I see your point. Were the answer edited, I would certainly revoke my downvote and keep my comment up.
    – Santana Afton
    Nov 29 '18 at 17:57











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1 Answer
1






active

oldest

votes








1 Answer
1






active

oldest

votes









active

oldest

votes






active

oldest

votes









3














The converse is obviously true. Since if $I$ satisfies the condition then $I$ cannot be contained in any proper ideal $J$ of $R$ because if $xin Jsetminus I$ then $R=Rx +Isubseteq J+Isubseteq J+J =J$.






share|cite|improve this answer



















  • 1




    Why the downvote? This is the obvious idea.
    – rschwieb
    Nov 29 '18 at 12:37










  • @rschwieb While this is the answer, I disagree that it is “obviously true” — it was certainly not obvious to the OP.
    – Santana Afton
    Nov 29 '18 at 12:46








  • 2




    +1 This is the very obvious idea, and I agree that it is obviously true.
    – Servaes
    Nov 29 '18 at 13:49












  • @SantanaAfton If you happened to assign a downvote for that reason, I'd just urge you to reconsider, since the sentiment (although you disagree with it) does not affect the correctness, quality or usefulness of the answer. Downvotes simply because one "does not like the way someone says something" are not very helpful to the community. Although, it would be completely natural to leave a comment opining that the answer would be better without the "obviously." :)
    – rschwieb
    Nov 29 '18 at 14:08












  • @rschwieb I voted not because I don’t like the “obvious” sentiment, but because I find such answers as less useful and of lower quality. That said, I see your point. Were the answer edited, I would certainly revoke my downvote and keep my comment up.
    – Santana Afton
    Nov 29 '18 at 17:57
















3














The converse is obviously true. Since if $I$ satisfies the condition then $I$ cannot be contained in any proper ideal $J$ of $R$ because if $xin Jsetminus I$ then $R=Rx +Isubseteq J+Isubseteq J+J =J$.






share|cite|improve this answer



















  • 1




    Why the downvote? This is the obvious idea.
    – rschwieb
    Nov 29 '18 at 12:37










  • @rschwieb While this is the answer, I disagree that it is “obviously true” — it was certainly not obvious to the OP.
    – Santana Afton
    Nov 29 '18 at 12:46








  • 2




    +1 This is the very obvious idea, and I agree that it is obviously true.
    – Servaes
    Nov 29 '18 at 13:49












  • @SantanaAfton If you happened to assign a downvote for that reason, I'd just urge you to reconsider, since the sentiment (although you disagree with it) does not affect the correctness, quality or usefulness of the answer. Downvotes simply because one "does not like the way someone says something" are not very helpful to the community. Although, it would be completely natural to leave a comment opining that the answer would be better without the "obviously." :)
    – rschwieb
    Nov 29 '18 at 14:08












  • @rschwieb I voted not because I don’t like the “obvious” sentiment, but because I find such answers as less useful and of lower quality. That said, I see your point. Were the answer edited, I would certainly revoke my downvote and keep my comment up.
    – Santana Afton
    Nov 29 '18 at 17:57














3












3








3






The converse is obviously true. Since if $I$ satisfies the condition then $I$ cannot be contained in any proper ideal $J$ of $R$ because if $xin Jsetminus I$ then $R=Rx +Isubseteq J+Isubseteq J+J =J$.






share|cite|improve this answer














The converse is obviously true. Since if $I$ satisfies the condition then $I$ cannot be contained in any proper ideal $J$ of $R$ because if $xin Jsetminus I$ then $R=Rx +Isubseteq J+Isubseteq J+J =J$.







share|cite|improve this answer














share|cite|improve this answer



share|cite|improve this answer








edited Nov 29 '18 at 18:30









rschwieb

105k1299244




105k1299244










answered Nov 29 '18 at 12:16









MotylaNogaTomkaMazura

6,542917




6,542917








  • 1




    Why the downvote? This is the obvious idea.
    – rschwieb
    Nov 29 '18 at 12:37










  • @rschwieb While this is the answer, I disagree that it is “obviously true” — it was certainly not obvious to the OP.
    – Santana Afton
    Nov 29 '18 at 12:46








  • 2




    +1 This is the very obvious idea, and I agree that it is obviously true.
    – Servaes
    Nov 29 '18 at 13:49












  • @SantanaAfton If you happened to assign a downvote for that reason, I'd just urge you to reconsider, since the sentiment (although you disagree with it) does not affect the correctness, quality or usefulness of the answer. Downvotes simply because one "does not like the way someone says something" are not very helpful to the community. Although, it would be completely natural to leave a comment opining that the answer would be better without the "obviously." :)
    – rschwieb
    Nov 29 '18 at 14:08












  • @rschwieb I voted not because I don’t like the “obvious” sentiment, but because I find such answers as less useful and of lower quality. That said, I see your point. Were the answer edited, I would certainly revoke my downvote and keep my comment up.
    – Santana Afton
    Nov 29 '18 at 17:57














  • 1




    Why the downvote? This is the obvious idea.
    – rschwieb
    Nov 29 '18 at 12:37










  • @rschwieb While this is the answer, I disagree that it is “obviously true” — it was certainly not obvious to the OP.
    – Santana Afton
    Nov 29 '18 at 12:46








  • 2




    +1 This is the very obvious idea, and I agree that it is obviously true.
    – Servaes
    Nov 29 '18 at 13:49












  • @SantanaAfton If you happened to assign a downvote for that reason, I'd just urge you to reconsider, since the sentiment (although you disagree with it) does not affect the correctness, quality or usefulness of the answer. Downvotes simply because one "does not like the way someone says something" are not very helpful to the community. Although, it would be completely natural to leave a comment opining that the answer would be better without the "obviously." :)
    – rschwieb
    Nov 29 '18 at 14:08












  • @rschwieb I voted not because I don’t like the “obvious” sentiment, but because I find such answers as less useful and of lower quality. That said, I see your point. Were the answer edited, I would certainly revoke my downvote and keep my comment up.
    – Santana Afton
    Nov 29 '18 at 17:57








1




1




Why the downvote? This is the obvious idea.
– rschwieb
Nov 29 '18 at 12:37




Why the downvote? This is the obvious idea.
– rschwieb
Nov 29 '18 at 12:37












@rschwieb While this is the answer, I disagree that it is “obviously true” — it was certainly not obvious to the OP.
– Santana Afton
Nov 29 '18 at 12:46






@rschwieb While this is the answer, I disagree that it is “obviously true” — it was certainly not obvious to the OP.
– Santana Afton
Nov 29 '18 at 12:46






2




2




+1 This is the very obvious idea, and I agree that it is obviously true.
– Servaes
Nov 29 '18 at 13:49






+1 This is the very obvious idea, and I agree that it is obviously true.
– Servaes
Nov 29 '18 at 13:49














@SantanaAfton If you happened to assign a downvote for that reason, I'd just urge you to reconsider, since the sentiment (although you disagree with it) does not affect the correctness, quality or usefulness of the answer. Downvotes simply because one "does not like the way someone says something" are not very helpful to the community. Although, it would be completely natural to leave a comment opining that the answer would be better without the "obviously." :)
– rschwieb
Nov 29 '18 at 14:08






@SantanaAfton If you happened to assign a downvote for that reason, I'd just urge you to reconsider, since the sentiment (although you disagree with it) does not affect the correctness, quality or usefulness of the answer. Downvotes simply because one "does not like the way someone says something" are not very helpful to the community. Although, it would be completely natural to leave a comment opining that the answer would be better without the "obviously." :)
– rschwieb
Nov 29 '18 at 14:08














@rschwieb I voted not because I don’t like the “obvious” sentiment, but because I find such answers as less useful and of lower quality. That said, I see your point. Were the answer edited, I would certainly revoke my downvote and keep my comment up.
– Santana Afton
Nov 29 '18 at 17:57




@rschwieb I voted not because I don’t like the “obvious” sentiment, but because I find such answers as less useful and of lower quality. That said, I see your point. Were the answer edited, I would certainly revoke my downvote and keep my comment up.
– Santana Afton
Nov 29 '18 at 17:57


















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