What's the definition of proper subspace of a vector space used in Rudin's Functional analysis












0












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I'm reading through the Rudin's functional analysis, and theorem 3.5 use the term "Proper Subspace", there's a theorem in chapter 2 that uses the same terminology.



I'm reading through chapter 1 again, and through the glossary as well but I cannot find the definition used.



I guess there must be a standard definition then,



What is such definition?










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  • 2




    $begingroup$
    It a subspace different from the vector space.
    $endgroup$
    – Bernard
    Nov 30 '18 at 10:29










  • $begingroup$
    So literally it's a proper subset that is also a vector space, correct?
    $endgroup$
    – user8469759
    Nov 30 '18 at 10:30












  • $begingroup$
    Yes, absolutely.
    $endgroup$
    – Bernard
    Nov 30 '18 at 10:33
















0












$begingroup$


I'm reading through the Rudin's functional analysis, and theorem 3.5 use the term "Proper Subspace", there's a theorem in chapter 2 that uses the same terminology.



I'm reading through chapter 1 again, and through the glossary as well but I cannot find the definition used.



I guess there must be a standard definition then,



What is such definition?










share|cite|improve this question









$endgroup$








  • 2




    $begingroup$
    It a subspace different from the vector space.
    $endgroup$
    – Bernard
    Nov 30 '18 at 10:29










  • $begingroup$
    So literally it's a proper subset that is also a vector space, correct?
    $endgroup$
    – user8469759
    Nov 30 '18 at 10:30












  • $begingroup$
    Yes, absolutely.
    $endgroup$
    – Bernard
    Nov 30 '18 at 10:33














0












0








0





$begingroup$


I'm reading through the Rudin's functional analysis, and theorem 3.5 use the term "Proper Subspace", there's a theorem in chapter 2 that uses the same terminology.



I'm reading through chapter 1 again, and through the glossary as well but I cannot find the definition used.



I guess there must be a standard definition then,



What is such definition?










share|cite|improve this question









$endgroup$




I'm reading through the Rudin's functional analysis, and theorem 3.5 use the term "Proper Subspace", there's a theorem in chapter 2 that uses the same terminology.



I'm reading through chapter 1 again, and through the glossary as well but I cannot find the definition used.



I guess there must be a standard definition then,



What is such definition?







functional-analysis vector-spaces definition topological-vector-spaces






share|cite|improve this question













share|cite|improve this question











share|cite|improve this question




share|cite|improve this question










asked Nov 30 '18 at 10:25









user8469759user8469759

1,3851617




1,3851617








  • 2




    $begingroup$
    It a subspace different from the vector space.
    $endgroup$
    – Bernard
    Nov 30 '18 at 10:29










  • $begingroup$
    So literally it's a proper subset that is also a vector space, correct?
    $endgroup$
    – user8469759
    Nov 30 '18 at 10:30












  • $begingroup$
    Yes, absolutely.
    $endgroup$
    – Bernard
    Nov 30 '18 at 10:33














  • 2




    $begingroup$
    It a subspace different from the vector space.
    $endgroup$
    – Bernard
    Nov 30 '18 at 10:29










  • $begingroup$
    So literally it's a proper subset that is also a vector space, correct?
    $endgroup$
    – user8469759
    Nov 30 '18 at 10:30












  • $begingroup$
    Yes, absolutely.
    $endgroup$
    – Bernard
    Nov 30 '18 at 10:33








2




2




$begingroup$
It a subspace different from the vector space.
$endgroup$
– Bernard
Nov 30 '18 at 10:29




$begingroup$
It a subspace different from the vector space.
$endgroup$
– Bernard
Nov 30 '18 at 10:29












$begingroup$
So literally it's a proper subset that is also a vector space, correct?
$endgroup$
– user8469759
Nov 30 '18 at 10:30






$begingroup$
So literally it's a proper subset that is also a vector space, correct?
$endgroup$
– user8469759
Nov 30 '18 at 10:30














$begingroup$
Yes, absolutely.
$endgroup$
– Bernard
Nov 30 '18 at 10:33




$begingroup$
Yes, absolutely.
$endgroup$
– Bernard
Nov 30 '18 at 10:33










1 Answer
1






active

oldest

votes


















2












$begingroup$

$V$ is a proper subspace of $X$ if
$V$ is a subspace of $X$ and $Vsubsetneq X$.



I would guess that there is no definition of proper subspace in the book,
since a proper subspace is a subspace that is also a proper subset.






share|cite|improve this answer











$endgroup$













  • $begingroup$
    Does this definition imply that the only proper subspace of $mathbb{R}$ is $left{ 0 right}$ and that proper subspaces of topological vector spaces have empty interiors?
    $endgroup$
    – user8469759
    Nov 30 '18 at 10:35












  • $begingroup$
    @user8469759 yes
    $endgroup$
    – supinf
    Nov 30 '18 at 10:35











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1 Answer
1






active

oldest

votes








1 Answer
1






active

oldest

votes









active

oldest

votes






active

oldest

votes









2












$begingroup$

$V$ is a proper subspace of $X$ if
$V$ is a subspace of $X$ and $Vsubsetneq X$.



I would guess that there is no definition of proper subspace in the book,
since a proper subspace is a subspace that is also a proper subset.






share|cite|improve this answer











$endgroup$













  • $begingroup$
    Does this definition imply that the only proper subspace of $mathbb{R}$ is $left{ 0 right}$ and that proper subspaces of topological vector spaces have empty interiors?
    $endgroup$
    – user8469759
    Nov 30 '18 at 10:35












  • $begingroup$
    @user8469759 yes
    $endgroup$
    – supinf
    Nov 30 '18 at 10:35
















2












$begingroup$

$V$ is a proper subspace of $X$ if
$V$ is a subspace of $X$ and $Vsubsetneq X$.



I would guess that there is no definition of proper subspace in the book,
since a proper subspace is a subspace that is also a proper subset.






share|cite|improve this answer











$endgroup$













  • $begingroup$
    Does this definition imply that the only proper subspace of $mathbb{R}$ is $left{ 0 right}$ and that proper subspaces of topological vector spaces have empty interiors?
    $endgroup$
    – user8469759
    Nov 30 '18 at 10:35












  • $begingroup$
    @user8469759 yes
    $endgroup$
    – supinf
    Nov 30 '18 at 10:35














2












2








2





$begingroup$

$V$ is a proper subspace of $X$ if
$V$ is a subspace of $X$ and $Vsubsetneq X$.



I would guess that there is no definition of proper subspace in the book,
since a proper subspace is a subspace that is also a proper subset.






share|cite|improve this answer











$endgroup$



$V$ is a proper subspace of $X$ if
$V$ is a subspace of $X$ and $Vsubsetneq X$.



I would guess that there is no definition of proper subspace in the book,
since a proper subspace is a subspace that is also a proper subset.







share|cite|improve this answer














share|cite|improve this answer



share|cite|improve this answer








edited Nov 30 '18 at 10:34

























answered Nov 30 '18 at 10:29









supinfsupinf

6,1241028




6,1241028












  • $begingroup$
    Does this definition imply that the only proper subspace of $mathbb{R}$ is $left{ 0 right}$ and that proper subspaces of topological vector spaces have empty interiors?
    $endgroup$
    – user8469759
    Nov 30 '18 at 10:35












  • $begingroup$
    @user8469759 yes
    $endgroup$
    – supinf
    Nov 30 '18 at 10:35


















  • $begingroup$
    Does this definition imply that the only proper subspace of $mathbb{R}$ is $left{ 0 right}$ and that proper subspaces of topological vector spaces have empty interiors?
    $endgroup$
    – user8469759
    Nov 30 '18 at 10:35












  • $begingroup$
    @user8469759 yes
    $endgroup$
    – supinf
    Nov 30 '18 at 10:35
















$begingroup$
Does this definition imply that the only proper subspace of $mathbb{R}$ is $left{ 0 right}$ and that proper subspaces of topological vector spaces have empty interiors?
$endgroup$
– user8469759
Nov 30 '18 at 10:35






$begingroup$
Does this definition imply that the only proper subspace of $mathbb{R}$ is $left{ 0 right}$ and that proper subspaces of topological vector spaces have empty interiors?
$endgroup$
– user8469759
Nov 30 '18 at 10:35














$begingroup$
@user8469759 yes
$endgroup$
– supinf
Nov 30 '18 at 10:35




$begingroup$
@user8469759 yes
$endgroup$
– supinf
Nov 30 '18 at 10:35


















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