Easiest way to prove that the operator is zero












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$begingroup$


If an operator $T in L(V)$ satisfies $Tv = 0$ for every $v in V$, then $T = 0$.



By the way, $V$ is a finite dimensional vector space.



Though, I am pretty certain that the statement is true, but I haven't proved it. Is there any way to prove that statement in an easy way?



(What I thought was, if we can represent that T in a basis of V, then if we put vectors $(1,0,...0), (0,1,...0), ... (0,0,...1)$, it is easy to show that all the entries of the matrix is zero which makes the operator $T$ an zero operator. However, I just wonder is there any shorter way to prove it)










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$endgroup$












  • $begingroup$
    How about using Contradiction? It works on the same idea but backwards. Assume that the operator is nonzero and design a $v$ such that $Tvneq0$?
    $endgroup$
    – Nitish
    Mar 19 '14 at 2:36










  • $begingroup$
    @Nitish I thought about that but I dont know how to come up a vector that $Tv neq 0$.
    $endgroup$
    – Jaebum
    Mar 19 '14 at 2:39










  • $begingroup$
    Is it a CIRCULAR question ?.
    $endgroup$
    – Felix Marin
    Mar 19 '14 at 2:43






  • 1




    $begingroup$
    What is the definition of two operators being equal? Check your textbook.
    $endgroup$
    – Omnomnomnom
    Mar 19 '14 at 2:45
















0












$begingroup$


If an operator $T in L(V)$ satisfies $Tv = 0$ for every $v in V$, then $T = 0$.



By the way, $V$ is a finite dimensional vector space.



Though, I am pretty certain that the statement is true, but I haven't proved it. Is there any way to prove that statement in an easy way?



(What I thought was, if we can represent that T in a basis of V, then if we put vectors $(1,0,...0), (0,1,...0), ... (0,0,...1)$, it is easy to show that all the entries of the matrix is zero which makes the operator $T$ an zero operator. However, I just wonder is there any shorter way to prove it)










share|cite|improve this question









$endgroup$












  • $begingroup$
    How about using Contradiction? It works on the same idea but backwards. Assume that the operator is nonzero and design a $v$ such that $Tvneq0$?
    $endgroup$
    – Nitish
    Mar 19 '14 at 2:36










  • $begingroup$
    @Nitish I thought about that but I dont know how to come up a vector that $Tv neq 0$.
    $endgroup$
    – Jaebum
    Mar 19 '14 at 2:39










  • $begingroup$
    Is it a CIRCULAR question ?.
    $endgroup$
    – Felix Marin
    Mar 19 '14 at 2:43






  • 1




    $begingroup$
    What is the definition of two operators being equal? Check your textbook.
    $endgroup$
    – Omnomnomnom
    Mar 19 '14 at 2:45














0












0








0





$begingroup$


If an operator $T in L(V)$ satisfies $Tv = 0$ for every $v in V$, then $T = 0$.



By the way, $V$ is a finite dimensional vector space.



Though, I am pretty certain that the statement is true, but I haven't proved it. Is there any way to prove that statement in an easy way?



(What I thought was, if we can represent that T in a basis of V, then if we put vectors $(1,0,...0), (0,1,...0), ... (0,0,...1)$, it is easy to show that all the entries of the matrix is zero which makes the operator $T$ an zero operator. However, I just wonder is there any shorter way to prove it)










share|cite|improve this question









$endgroup$




If an operator $T in L(V)$ satisfies $Tv = 0$ for every $v in V$, then $T = 0$.



By the way, $V$ is a finite dimensional vector space.



Though, I am pretty certain that the statement is true, but I haven't proved it. Is there any way to prove that statement in an easy way?



(What I thought was, if we can represent that T in a basis of V, then if we put vectors $(1,0,...0), (0,1,...0), ... (0,0,...1)$, it is easy to show that all the entries of the matrix is zero which makes the operator $T$ an zero operator. However, I just wonder is there any shorter way to prove it)







linear-algebra matrices






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asked Mar 19 '14 at 2:31









JaebumJaebum

1063




1063












  • $begingroup$
    How about using Contradiction? It works on the same idea but backwards. Assume that the operator is nonzero and design a $v$ such that $Tvneq0$?
    $endgroup$
    – Nitish
    Mar 19 '14 at 2:36










  • $begingroup$
    @Nitish I thought about that but I dont know how to come up a vector that $Tv neq 0$.
    $endgroup$
    – Jaebum
    Mar 19 '14 at 2:39










  • $begingroup$
    Is it a CIRCULAR question ?.
    $endgroup$
    – Felix Marin
    Mar 19 '14 at 2:43






  • 1




    $begingroup$
    What is the definition of two operators being equal? Check your textbook.
    $endgroup$
    – Omnomnomnom
    Mar 19 '14 at 2:45


















  • $begingroup$
    How about using Contradiction? It works on the same idea but backwards. Assume that the operator is nonzero and design a $v$ such that $Tvneq0$?
    $endgroup$
    – Nitish
    Mar 19 '14 at 2:36










  • $begingroup$
    @Nitish I thought about that but I dont know how to come up a vector that $Tv neq 0$.
    $endgroup$
    – Jaebum
    Mar 19 '14 at 2:39










  • $begingroup$
    Is it a CIRCULAR question ?.
    $endgroup$
    – Felix Marin
    Mar 19 '14 at 2:43






  • 1




    $begingroup$
    What is the definition of two operators being equal? Check your textbook.
    $endgroup$
    – Omnomnomnom
    Mar 19 '14 at 2:45
















$begingroup$
How about using Contradiction? It works on the same idea but backwards. Assume that the operator is nonzero and design a $v$ such that $Tvneq0$?
$endgroup$
– Nitish
Mar 19 '14 at 2:36




$begingroup$
How about using Contradiction? It works on the same idea but backwards. Assume that the operator is nonzero and design a $v$ such that $Tvneq0$?
$endgroup$
– Nitish
Mar 19 '14 at 2:36












$begingroup$
@Nitish I thought about that but I dont know how to come up a vector that $Tv neq 0$.
$endgroup$
– Jaebum
Mar 19 '14 at 2:39




$begingroup$
@Nitish I thought about that but I dont know how to come up a vector that $Tv neq 0$.
$endgroup$
– Jaebum
Mar 19 '14 at 2:39












$begingroup$
Is it a CIRCULAR question ?.
$endgroup$
– Felix Marin
Mar 19 '14 at 2:43




$begingroup$
Is it a CIRCULAR question ?.
$endgroup$
– Felix Marin
Mar 19 '14 at 2:43




1




1




$begingroup$
What is the definition of two operators being equal? Check your textbook.
$endgroup$
– Omnomnomnom
Mar 19 '14 at 2:45




$begingroup$
What is the definition of two operators being equal? Check your textbook.
$endgroup$
– Omnomnomnom
Mar 19 '14 at 2:45










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$begingroup$

"$T=0$" means "$Tv=0$ for all $vin V$". There is nothing to prove.






share|cite|improve this answer









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    0












    $begingroup$

    "$T=0$" means "$Tv=0$ for all $vin V$". There is nothing to prove.






    share|cite|improve this answer









    $endgroup$


















      0












      $begingroup$

      "$T=0$" means "$Tv=0$ for all $vin V$". There is nothing to prove.






      share|cite|improve this answer









      $endgroup$
















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        0





        $begingroup$

        "$T=0$" means "$Tv=0$ for all $vin V$". There is nothing to prove.






        share|cite|improve this answer









        $endgroup$



        "$T=0$" means "$Tv=0$ for all $vin V$". There is nothing to prove.







        share|cite|improve this answer












        share|cite|improve this answer



        share|cite|improve this answer










        answered Mar 20 '14 at 1:05









        Martin ArgeramiMartin Argerami

        127k1182183




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