Definition of span

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On an old midterm exam, my professor requested the students prove that




The span of $S$ (where $S$ is a subset of a vector space $V$) is equal to all vectors that can be expressed as linear combinations of the elements in $S$.




Does this make any sense? He's requesting we show that the span of $S$ equals what I believe to be the definition of span. Is there possibly some other definition of span that I should be aware of?










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  • And of course the true insight is that one proves the equivalence of all these properties and thereby is motivated to define the notion of span (as any and all of these) in the first place ...
    – Hagen von Eitzen
    1 hour ago














up vote
2
down vote

favorite












On an old midterm exam, my professor requested the students prove that




The span of $S$ (where $S$ is a subset of a vector space $V$) is equal to all vectors that can be expressed as linear combinations of the elements in $S$.




Does this make any sense? He's requesting we show that the span of $S$ equals what I believe to be the definition of span. Is there possibly some other definition of span that I should be aware of?










share|cite|improve this question























  • And of course the true insight is that one proves the equivalence of all these properties and thereby is motivated to define the notion of span (as any and all of these) in the first place ...
    – Hagen von Eitzen
    1 hour ago












up vote
2
down vote

favorite









up vote
2
down vote

favorite











On an old midterm exam, my professor requested the students prove that




The span of $S$ (where $S$ is a subset of a vector space $V$) is equal to all vectors that can be expressed as linear combinations of the elements in $S$.




Does this make any sense? He's requesting we show that the span of $S$ equals what I believe to be the definition of span. Is there possibly some other definition of span that I should be aware of?










share|cite|improve this question















On an old midterm exam, my professor requested the students prove that




The span of $S$ (where $S$ is a subset of a vector space $V$) is equal to all vectors that can be expressed as linear combinations of the elements in $S$.




Does this make any sense? He's requesting we show that the span of $S$ equals what I believe to be the definition of span. Is there possibly some other definition of span that I should be aware of?







linear-algebra vector-spaces definition






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edited 1 hour ago









José Carlos Santos

128k17103191




128k17103191










asked 1 hour ago









DavidS

161110




161110











  • And of course the true insight is that one proves the equivalence of all these properties and thereby is motivated to define the notion of span (as any and all of these) in the first place ...
    – Hagen von Eitzen
    1 hour ago
















  • And of course the true insight is that one proves the equivalence of all these properties and thereby is motivated to define the notion of span (as any and all of these) in the first place ...
    – Hagen von Eitzen
    1 hour ago















And of course the true insight is that one proves the equivalence of all these properties and thereby is motivated to define the notion of span (as any and all of these) in the first place ...
– Hagen von Eitzen
1 hour ago




And of course the true insight is that one proves the equivalence of all these properties and thereby is motivated to define the notion of span (as any and all of these) in the first place ...
– Hagen von Eitzen
1 hour ago










3 Answers
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Yes, there is another definition: let$$mathcalW=bigcapleftWsubset V,middle.$$Now, define $operatornamespanS=bigcap_Winmathcal WW$.






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    Perhaps the definition of span that your professor is using is: The smallest vector space generated by the vectors in the spanning set.






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      You can define $textspan (S)$ to be the smallest vector subspace containing $S$, or equivalently the intersection all vector subspaces containing $S$. Such a definition is very common in algebra.






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        3 Answers
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        3 Answers
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        up vote
        3
        down vote













        Yes, there is another definition: let$$mathcalW=bigcapleftWsubset V,middle.$$Now, define $operatornamespanS=bigcap_Winmathcal WW$.






        share|cite|improve this answer
























          up vote
          3
          down vote













          Yes, there is another definition: let$$mathcalW=bigcapleftWsubset V,middle.$$Now, define $operatornamespanS=bigcap_Winmathcal WW$.






          share|cite|improve this answer






















            up vote
            3
            down vote










            up vote
            3
            down vote









            Yes, there is another definition: let$$mathcalW=bigcapleftWsubset V,middle.$$Now, define $operatornamespanS=bigcap_Winmathcal WW$.






            share|cite|improve this answer












            Yes, there is another definition: let$$mathcalW=bigcapleftWsubset V,middle.$$Now, define $operatornamespanS=bigcap_Winmathcal WW$.







            share|cite|improve this answer












            share|cite|improve this answer



            share|cite|improve this answer










            answered 1 hour ago









            José Carlos Santos

            128k17103191




            128k17103191




















                up vote
                3
                down vote













                Perhaps the definition of span that your professor is using is: The smallest vector space generated by the vectors in the spanning set.






                share|cite|improve this answer
























                  up vote
                  3
                  down vote













                  Perhaps the definition of span that your professor is using is: The smallest vector space generated by the vectors in the spanning set.






                  share|cite|improve this answer






















                    up vote
                    3
                    down vote










                    up vote
                    3
                    down vote









                    Perhaps the definition of span that your professor is using is: The smallest vector space generated by the vectors in the spanning set.






                    share|cite|improve this answer












                    Perhaps the definition of span that your professor is using is: The smallest vector space generated by the vectors in the spanning set.







                    share|cite|improve this answer












                    share|cite|improve this answer



                    share|cite|improve this answer










                    answered 1 hour ago









                    ervx

                    9,81331337




                    9,81331337




















                        up vote
                        3
                        down vote













                        You can define $textspan (S)$ to be the smallest vector subspace containing $S$, or equivalently the intersection all vector subspaces containing $S$. Such a definition is very common in algebra.






                        share|cite|improve this answer
























                          up vote
                          3
                          down vote













                          You can define $textspan (S)$ to be the smallest vector subspace containing $S$, or equivalently the intersection all vector subspaces containing $S$. Such a definition is very common in algebra.






                          share|cite|improve this answer






















                            up vote
                            3
                            down vote










                            up vote
                            3
                            down vote









                            You can define $textspan (S)$ to be the smallest vector subspace containing $S$, or equivalently the intersection all vector subspaces containing $S$. Such a definition is very common in algebra.






                            share|cite|improve this answer












                            You can define $textspan (S)$ to be the smallest vector subspace containing $S$, or equivalently the intersection all vector subspaces containing $S$. Such a definition is very common in algebra.







                            share|cite|improve this answer












                            share|cite|improve this answer



                            share|cite|improve this answer










                            answered 1 hour ago









                            Foobaz John

                            18.9k41245




                            18.9k41245



























                                 

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