For subsets $Msubset N$ of a vector space, $langle{Mrangle}subset langle{Nrangle}$.












0












$begingroup$


Hello I had to prove that $Msubset N$ implies $langle{M}rangle subset langle{M}rangle$ for $M, N$ subsets of a vector space.
My idea looks like the following:
Suppose $ M = {v_1, ..., v_m} $ and $ N = {v_1, ..., v_n} $ $with space 1 leq m leq n space m,n in N$
From that it follows by applying the definition of a linear hull:
$$〈M〉=K cdot v_1 + ... + K cdot v_m$$ and $$〈N〉=K cdot v_1 + ... + K cdot v_n$$
Because m<=n it follows that 〈M〉⊂〈N〉



Apparently that was the wrong way to do it though as i assumed that the sets are finite. Can somebody help me out here? How do you proof this correctly? Thanks in advance!










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$endgroup$












  • $begingroup$
    How is $K$ defined?
    $endgroup$
    – Anurag A
    Dec 1 '18 at 0:28










  • $begingroup$
    K is just a scalar. If my vectorspace was $R^3$ then K would be $R$.
    $endgroup$
    – D. John
    Dec 1 '18 at 0:33










  • $begingroup$
    $M subseteq N subseteq langle N rangle$, so $langle N rangle$ is a subspace containing $M$. Since $langle M rangle$ is the smallest subspace containing $M$ (i.e. it is the intersection of all subspaces containing $M$), we conclude that $langle M rangle subseteq langle N rangle$.
    $endgroup$
    – Bungo
    Dec 1 '18 at 2:13


















0












$begingroup$


Hello I had to prove that $Msubset N$ implies $langle{M}rangle subset langle{M}rangle$ for $M, N$ subsets of a vector space.
My idea looks like the following:
Suppose $ M = {v_1, ..., v_m} $ and $ N = {v_1, ..., v_n} $ $with space 1 leq m leq n space m,n in N$
From that it follows by applying the definition of a linear hull:
$$〈M〉=K cdot v_1 + ... + K cdot v_m$$ and $$〈N〉=K cdot v_1 + ... + K cdot v_n$$
Because m<=n it follows that 〈M〉⊂〈N〉



Apparently that was the wrong way to do it though as i assumed that the sets are finite. Can somebody help me out here? How do you proof this correctly? Thanks in advance!










share|cite|improve this question











$endgroup$












  • $begingroup$
    How is $K$ defined?
    $endgroup$
    – Anurag A
    Dec 1 '18 at 0:28










  • $begingroup$
    K is just a scalar. If my vectorspace was $R^3$ then K would be $R$.
    $endgroup$
    – D. John
    Dec 1 '18 at 0:33










  • $begingroup$
    $M subseteq N subseteq langle N rangle$, so $langle N rangle$ is a subspace containing $M$. Since $langle M rangle$ is the smallest subspace containing $M$ (i.e. it is the intersection of all subspaces containing $M$), we conclude that $langle M rangle subseteq langle N rangle$.
    $endgroup$
    – Bungo
    Dec 1 '18 at 2:13
















0












0








0





$begingroup$


Hello I had to prove that $Msubset N$ implies $langle{M}rangle subset langle{M}rangle$ for $M, N$ subsets of a vector space.
My idea looks like the following:
Suppose $ M = {v_1, ..., v_m} $ and $ N = {v_1, ..., v_n} $ $with space 1 leq m leq n space m,n in N$
From that it follows by applying the definition of a linear hull:
$$〈M〉=K cdot v_1 + ... + K cdot v_m$$ and $$〈N〉=K cdot v_1 + ... + K cdot v_n$$
Because m<=n it follows that 〈M〉⊂〈N〉



Apparently that was the wrong way to do it though as i assumed that the sets are finite. Can somebody help me out here? How do you proof this correctly? Thanks in advance!










share|cite|improve this question











$endgroup$




Hello I had to prove that $Msubset N$ implies $langle{M}rangle subset langle{M}rangle$ for $M, N$ subsets of a vector space.
My idea looks like the following:
Suppose $ M = {v_1, ..., v_m} $ and $ N = {v_1, ..., v_n} $ $with space 1 leq m leq n space m,n in N$
From that it follows by applying the definition of a linear hull:
$$〈M〉=K cdot v_1 + ... + K cdot v_m$$ and $$〈N〉=K cdot v_1 + ... + K cdot v_n$$
Because m<=n it follows that 〈M〉⊂〈N〉



Apparently that was the wrong way to do it though as i assumed that the sets are finite. Can somebody help me out here? How do you proof this correctly? Thanks in advance!







linear-algebra proof-writing






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share|cite|improve this question













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edited Dec 1 '18 at 2:04









anomaly

17.4k42664




17.4k42664










asked Dec 1 '18 at 0:22









D. JohnD. John

283




283












  • $begingroup$
    How is $K$ defined?
    $endgroup$
    – Anurag A
    Dec 1 '18 at 0:28










  • $begingroup$
    K is just a scalar. If my vectorspace was $R^3$ then K would be $R$.
    $endgroup$
    – D. John
    Dec 1 '18 at 0:33










  • $begingroup$
    $M subseteq N subseteq langle N rangle$, so $langle N rangle$ is a subspace containing $M$. Since $langle M rangle$ is the smallest subspace containing $M$ (i.e. it is the intersection of all subspaces containing $M$), we conclude that $langle M rangle subseteq langle N rangle$.
    $endgroup$
    – Bungo
    Dec 1 '18 at 2:13




















  • $begingroup$
    How is $K$ defined?
    $endgroup$
    – Anurag A
    Dec 1 '18 at 0:28










  • $begingroup$
    K is just a scalar. If my vectorspace was $R^3$ then K would be $R$.
    $endgroup$
    – D. John
    Dec 1 '18 at 0:33










  • $begingroup$
    $M subseteq N subseteq langle N rangle$, so $langle N rangle$ is a subspace containing $M$. Since $langle M rangle$ is the smallest subspace containing $M$ (i.e. it is the intersection of all subspaces containing $M$), we conclude that $langle M rangle subseteq langle N rangle$.
    $endgroup$
    – Bungo
    Dec 1 '18 at 2:13


















$begingroup$
How is $K$ defined?
$endgroup$
– Anurag A
Dec 1 '18 at 0:28




$begingroup$
How is $K$ defined?
$endgroup$
– Anurag A
Dec 1 '18 at 0:28












$begingroup$
K is just a scalar. If my vectorspace was $R^3$ then K would be $R$.
$endgroup$
– D. John
Dec 1 '18 at 0:33




$begingroup$
K is just a scalar. If my vectorspace was $R^3$ then K would be $R$.
$endgroup$
– D. John
Dec 1 '18 at 0:33












$begingroup$
$M subseteq N subseteq langle N rangle$, so $langle N rangle$ is a subspace containing $M$. Since $langle M rangle$ is the smallest subspace containing $M$ (i.e. it is the intersection of all subspaces containing $M$), we conclude that $langle M rangle subseteq langle N rangle$.
$endgroup$
– Bungo
Dec 1 '18 at 2:13






$begingroup$
$M subseteq N subseteq langle N rangle$, so $langle N rangle$ is a subspace containing $M$. Since $langle M rangle$ is the smallest subspace containing $M$ (i.e. it is the intersection of all subspaces containing $M$), we conclude that $langle M rangle subseteq langle N rangle$.
$endgroup$
– Bungo
Dec 1 '18 at 2:13












2 Answers
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$begingroup$

For a vector space $V$ and a subset $Xsubset V$, the space $langle{X}rangle$ is by definition or construction the minimal subspace of $V$ containing $X$. But $langle{Nrangle}$ then also contains $Msubset N$, and so it must also contain $langle{Mrangle}$.






share|cite|improve this answer











$endgroup$





















    1












    $begingroup$

    Since M $subset$ N, every vector of M is also a vector of N. So a linear combination of elements of M can be viewed as a linear combination of elements in N. Thus $<M> subset<N>.$






    share|cite|improve this answer









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      2 Answers
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      2 Answers
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      $begingroup$

      For a vector space $V$ and a subset $Xsubset V$, the space $langle{X}rangle$ is by definition or construction the minimal subspace of $V$ containing $X$. But $langle{Nrangle}$ then also contains $Msubset N$, and so it must also contain $langle{Mrangle}$.






      share|cite|improve this answer











      $endgroup$


















        1












        $begingroup$

        For a vector space $V$ and a subset $Xsubset V$, the space $langle{X}rangle$ is by definition or construction the minimal subspace of $V$ containing $X$. But $langle{Nrangle}$ then also contains $Msubset N$, and so it must also contain $langle{Mrangle}$.






        share|cite|improve this answer











        $endgroup$
















          1












          1








          1





          $begingroup$

          For a vector space $V$ and a subset $Xsubset V$, the space $langle{X}rangle$ is by definition or construction the minimal subspace of $V$ containing $X$. But $langle{Nrangle}$ then also contains $Msubset N$, and so it must also contain $langle{Mrangle}$.






          share|cite|improve this answer











          $endgroup$



          For a vector space $V$ and a subset $Xsubset V$, the space $langle{X}rangle$ is by definition or construction the minimal subspace of $V$ containing $X$. But $langle{Nrangle}$ then also contains $Msubset N$, and so it must also contain $langle{Mrangle}$.







          share|cite|improve this answer














          share|cite|improve this answer



          share|cite|improve this answer








          edited Dec 1 '18 at 2:22

























          answered Dec 1 '18 at 2:06









          anomalyanomaly

          17.4k42664




          17.4k42664























              1












              $begingroup$

              Since M $subset$ N, every vector of M is also a vector of N. So a linear combination of elements of M can be viewed as a linear combination of elements in N. Thus $<M> subset<N>.$






              share|cite|improve this answer









              $endgroup$


















                1












                $begingroup$

                Since M $subset$ N, every vector of M is also a vector of N. So a linear combination of elements of M can be viewed as a linear combination of elements in N. Thus $<M> subset<N>.$






                share|cite|improve this answer









                $endgroup$
















                  1












                  1








                  1





                  $begingroup$

                  Since M $subset$ N, every vector of M is also a vector of N. So a linear combination of elements of M can be viewed as a linear combination of elements in N. Thus $<M> subset<N>.$






                  share|cite|improve this answer









                  $endgroup$



                  Since M $subset$ N, every vector of M is also a vector of N. So a linear combination of elements of M can be viewed as a linear combination of elements in N. Thus $<M> subset<N>.$







                  share|cite|improve this answer












                  share|cite|improve this answer



                  share|cite|improve this answer










                  answered Dec 1 '18 at 1:45









                  Joel PereiraJoel Pereira

                  73519




                  73519






























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