$mathbb Z [X] / (X)$ isomorphic to $mathbb Z[X] / (X+1)$ isomorphic to $mathbb Z [X] / (X+2015)$












0












$begingroup$


I have to prove that $mathbb Z [X] / (X) cong mathbb Z[X] / (X+1) cong mathbb Z [X] / (X+2015)$.



I think that one answer could be that $mathbb Z[X]/(X) cong mathbb Z(0)$, $mathbb Z[X]/(X+1)cong Z(-1)$ and $mathbb Z [X] /(X+2015)cong mathbb Z(-2015)$, as $0, -1, -2015$ are roots of these polynomials. Also, as $0, -1, -2015in mathbb Z$, then all of them are isomorphic to $mathbb Z $, hence isomorphic between them.



But I don't know very well how to justify this rigorously and my teacher has said to me that there is a simpler way to proof this, without using the roots of these polynomials.










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$endgroup$

















    0












    $begingroup$


    I have to prove that $mathbb Z [X] / (X) cong mathbb Z[X] / (X+1) cong mathbb Z [X] / (X+2015)$.



    I think that one answer could be that $mathbb Z[X]/(X) cong mathbb Z(0)$, $mathbb Z[X]/(X+1)cong Z(-1)$ and $mathbb Z [X] /(X+2015)cong mathbb Z(-2015)$, as $0, -1, -2015$ are roots of these polynomials. Also, as $0, -1, -2015in mathbb Z$, then all of them are isomorphic to $mathbb Z $, hence isomorphic between them.



    But I don't know very well how to justify this rigorously and my teacher has said to me that there is a simpler way to proof this, without using the roots of these polynomials.










    share|cite|improve this question









    $endgroup$















      0












      0








      0





      $begingroup$


      I have to prove that $mathbb Z [X] / (X) cong mathbb Z[X] / (X+1) cong mathbb Z [X] / (X+2015)$.



      I think that one answer could be that $mathbb Z[X]/(X) cong mathbb Z(0)$, $mathbb Z[X]/(X+1)cong Z(-1)$ and $mathbb Z [X] /(X+2015)cong mathbb Z(-2015)$, as $0, -1, -2015$ are roots of these polynomials. Also, as $0, -1, -2015in mathbb Z$, then all of them are isomorphic to $mathbb Z $, hence isomorphic between them.



      But I don't know very well how to justify this rigorously and my teacher has said to me that there is a simpler way to proof this, without using the roots of these polynomials.










      share|cite|improve this question









      $endgroup$




      I have to prove that $mathbb Z [X] / (X) cong mathbb Z[X] / (X+1) cong mathbb Z [X] / (X+2015)$.



      I think that one answer could be that $mathbb Z[X]/(X) cong mathbb Z(0)$, $mathbb Z[X]/(X+1)cong Z(-1)$ and $mathbb Z [X] /(X+2015)cong mathbb Z(-2015)$, as $0, -1, -2015$ are roots of these polynomials. Also, as $0, -1, -2015in mathbb Z$, then all of them are isomorphic to $mathbb Z $, hence isomorphic between them.



      But I don't know very well how to justify this rigorously and my teacher has said to me that there is a simpler way to proof this, without using the roots of these polynomials.







      abstract-algebra ring-theory






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      asked Mar 30 '15 at 10:37









      mkspkmkspk

      553617




      553617






















          1 Answer
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          $begingroup$

          Some ideas:



          Define



          $$phi:Bbb Z[x]toBbb Z[x]/langle x+1rangle;,;;phi(p(x)):=p(x+1)+langle x+1rangle$$



          Show that this is a homomorphism, and now: what is its kernel? You may want to apply the first isomorphism theorem.






          share|cite|improve this answer











          $endgroup$













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            1 Answer
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            1 Answer
            1






            active

            oldest

            votes









            active

            oldest

            votes






            active

            oldest

            votes









            2












            $begingroup$

            Some ideas:



            Define



            $$phi:Bbb Z[x]toBbb Z[x]/langle x+1rangle;,;;phi(p(x)):=p(x+1)+langle x+1rangle$$



            Show that this is a homomorphism, and now: what is its kernel? You may want to apply the first isomorphism theorem.






            share|cite|improve this answer











            $endgroup$


















              2












              $begingroup$

              Some ideas:



              Define



              $$phi:Bbb Z[x]toBbb Z[x]/langle x+1rangle;,;;phi(p(x)):=p(x+1)+langle x+1rangle$$



              Show that this is a homomorphism, and now: what is its kernel? You may want to apply the first isomorphism theorem.






              share|cite|improve this answer











              $endgroup$
















                2












                2








                2





                $begingroup$

                Some ideas:



                Define



                $$phi:Bbb Z[x]toBbb Z[x]/langle x+1rangle;,;;phi(p(x)):=p(x+1)+langle x+1rangle$$



                Show that this is a homomorphism, and now: what is its kernel? You may want to apply the first isomorphism theorem.






                share|cite|improve this answer











                $endgroup$



                Some ideas:



                Define



                $$phi:Bbb Z[x]toBbb Z[x]/langle x+1rangle;,;;phi(p(x)):=p(x+1)+langle x+1rangle$$



                Show that this is a homomorphism, and now: what is its kernel? You may want to apply the first isomorphism theorem.







                share|cite|improve this answer














                share|cite|improve this answer



                share|cite|improve this answer








                edited Mar 30 '15 at 11:12

























                answered Mar 30 '15 at 10:41









                TimbucTimbuc

                30.9k22145




                30.9k22145






























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