Show that the center of a division ring is a field.











up vote
1
down vote

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1












I tried the proof, but wasn't able to proceed further:
let a and b be any elements belonging to Z(center),
Now a.b=b.a
hence Z is commutative.



Now proving that Z is a division ring:(then we can show that since every commutative division ring is field, Z is a field)
NO CLUE...










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  • 2




    Take an element in the center and show its inverse is in the center too
    – gd1035
    Nov 15 at 20:51










  • I am sorry but, i am not getting how will it help?
    – Cosmic
    Nov 15 at 20:56






  • 1




    Z is a division ring if $zin$ Z $rightarrowexists yin$ Z such that $zy=1$, so you just need to take an arbitrary element in Z and show that its inverse is in Z
    – gd1035
    Nov 15 at 21:08

















up vote
1
down vote

favorite
1












I tried the proof, but wasn't able to proceed further:
let a and b be any elements belonging to Z(center),
Now a.b=b.a
hence Z is commutative.



Now proving that Z is a division ring:(then we can show that since every commutative division ring is field, Z is a field)
NO CLUE...










share|cite|improve this question


















  • 2




    Take an element in the center and show its inverse is in the center too
    – gd1035
    Nov 15 at 20:51










  • I am sorry but, i am not getting how will it help?
    – Cosmic
    Nov 15 at 20:56






  • 1




    Z is a division ring if $zin$ Z $rightarrowexists yin$ Z such that $zy=1$, so you just need to take an arbitrary element in Z and show that its inverse is in Z
    – gd1035
    Nov 15 at 21:08















up vote
1
down vote

favorite
1









up vote
1
down vote

favorite
1






1





I tried the proof, but wasn't able to proceed further:
let a and b be any elements belonging to Z(center),
Now a.b=b.a
hence Z is commutative.



Now proving that Z is a division ring:(then we can show that since every commutative division ring is field, Z is a field)
NO CLUE...










share|cite|improve this question













I tried the proof, but wasn't able to proceed further:
let a and b be any elements belonging to Z(center),
Now a.b=b.a
hence Z is commutative.



Now proving that Z is a division ring:(then we can show that since every commutative division ring is field, Z is a field)
NO CLUE...







abstract-algebra ring-theory






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share|cite|improve this question











share|cite|improve this question




share|cite|improve this question










asked Nov 15 at 20:50









Cosmic

448




448








  • 2




    Take an element in the center and show its inverse is in the center too
    – gd1035
    Nov 15 at 20:51










  • I am sorry but, i am not getting how will it help?
    – Cosmic
    Nov 15 at 20:56






  • 1




    Z is a division ring if $zin$ Z $rightarrowexists yin$ Z such that $zy=1$, so you just need to take an arbitrary element in Z and show that its inverse is in Z
    – gd1035
    Nov 15 at 21:08
















  • 2




    Take an element in the center and show its inverse is in the center too
    – gd1035
    Nov 15 at 20:51










  • I am sorry but, i am not getting how will it help?
    – Cosmic
    Nov 15 at 20:56






  • 1




    Z is a division ring if $zin$ Z $rightarrowexists yin$ Z such that $zy=1$, so you just need to take an arbitrary element in Z and show that its inverse is in Z
    – gd1035
    Nov 15 at 21:08










2




2




Take an element in the center and show its inverse is in the center too
– gd1035
Nov 15 at 20:51




Take an element in the center and show its inverse is in the center too
– gd1035
Nov 15 at 20:51












I am sorry but, i am not getting how will it help?
– Cosmic
Nov 15 at 20:56




I am sorry but, i am not getting how will it help?
– Cosmic
Nov 15 at 20:56




1




1




Z is a division ring if $zin$ Z $rightarrowexists yin$ Z such that $zy=1$, so you just need to take an arbitrary element in Z and show that its inverse is in Z
– gd1035
Nov 15 at 21:08






Z is a division ring if $zin$ Z $rightarrowexists yin$ Z such that $zy=1$, so you just need to take an arbitrary element in Z and show that its inverse is in Z
– gd1035
Nov 15 at 21:08












1 Answer
1






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up vote
3
down vote



accepted










Hopefully you can already prove:




The center of a ring is a ring, in fact, a commutative ring.




Furthermore, if $D$ is a division ring, then for all $xin Z(D)$, if $xneq 0$, then $x^{-1}$ exists somewhere in $D$.



Now to show the commutative ring $Z(D)$ is a field, you'd have to show that $x^{-1}in Z(D)$, because inverses are unique, and a field necessarily has inverses for its nonzero elements.



So, the task is clear: if $0neq xin Z(D)$, prove $x^{-1}in Z(D)$.






share|cite|improve this answer





















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    1 Answer
    1






    active

    oldest

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    1 Answer
    1






    active

    oldest

    votes









    active

    oldest

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    active

    oldest

    votes








    up vote
    3
    down vote



    accepted










    Hopefully you can already prove:




    The center of a ring is a ring, in fact, a commutative ring.




    Furthermore, if $D$ is a division ring, then for all $xin Z(D)$, if $xneq 0$, then $x^{-1}$ exists somewhere in $D$.



    Now to show the commutative ring $Z(D)$ is a field, you'd have to show that $x^{-1}in Z(D)$, because inverses are unique, and a field necessarily has inverses for its nonzero elements.



    So, the task is clear: if $0neq xin Z(D)$, prove $x^{-1}in Z(D)$.






    share|cite|improve this answer

























      up vote
      3
      down vote



      accepted










      Hopefully you can already prove:




      The center of a ring is a ring, in fact, a commutative ring.




      Furthermore, if $D$ is a division ring, then for all $xin Z(D)$, if $xneq 0$, then $x^{-1}$ exists somewhere in $D$.



      Now to show the commutative ring $Z(D)$ is a field, you'd have to show that $x^{-1}in Z(D)$, because inverses are unique, and a field necessarily has inverses for its nonzero elements.



      So, the task is clear: if $0neq xin Z(D)$, prove $x^{-1}in Z(D)$.






      share|cite|improve this answer























        up vote
        3
        down vote



        accepted







        up vote
        3
        down vote



        accepted






        Hopefully you can already prove:




        The center of a ring is a ring, in fact, a commutative ring.




        Furthermore, if $D$ is a division ring, then for all $xin Z(D)$, if $xneq 0$, then $x^{-1}$ exists somewhere in $D$.



        Now to show the commutative ring $Z(D)$ is a field, you'd have to show that $x^{-1}in Z(D)$, because inverses are unique, and a field necessarily has inverses for its nonzero elements.



        So, the task is clear: if $0neq xin Z(D)$, prove $x^{-1}in Z(D)$.






        share|cite|improve this answer












        Hopefully you can already prove:




        The center of a ring is a ring, in fact, a commutative ring.




        Furthermore, if $D$ is a division ring, then for all $xin Z(D)$, if $xneq 0$, then $x^{-1}$ exists somewhere in $D$.



        Now to show the commutative ring $Z(D)$ is a field, you'd have to show that $x^{-1}in Z(D)$, because inverses are unique, and a field necessarily has inverses for its nonzero elements.



        So, the task is clear: if $0neq xin Z(D)$, prove $x^{-1}in Z(D)$.







        share|cite|improve this answer












        share|cite|improve this answer



        share|cite|improve this answer










        answered Nov 15 at 22:23









        rschwieb

        103k1299238




        103k1299238






























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