Basis for vector space $F(X,V)$ of functions mapping any arbitrary set to a vector space
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How would I go about determining the basis for the vector space $F(X,V)$ of all functions mapping an element of any arbitrary set $X$ to some vector space $V$ with the usual definition of addition and scalar multiplication on functions, should I already know the basis for that vector space?
I tried to extend the notion of the basis of the vector space of linear maps $F(X,F)$ from some set $X={a_0,...,a_n}$ to an arbitrary field where the basis was made up of functions defined as $f_i(a_j)=1$ when $i=j$ and $0$ otherwise. However I have had no such luck developing the idea for $F(X,V)$.
linear-algebra vector-spaces hamel-basis
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add a comment |
$begingroup$
How would I go about determining the basis for the vector space $F(X,V)$ of all functions mapping an element of any arbitrary set $X$ to some vector space $V$ with the usual definition of addition and scalar multiplication on functions, should I already know the basis for that vector space?
I tried to extend the notion of the basis of the vector space of linear maps $F(X,F)$ from some set $X={a_0,...,a_n}$ to an arbitrary field where the basis was made up of functions defined as $f_i(a_j)=1$ when $i=j$ and $0$ otherwise. However I have had no such luck developing the idea for $F(X,V)$.
linear-algebra vector-spaces hamel-basis
$endgroup$
add a comment |
$begingroup$
How would I go about determining the basis for the vector space $F(X,V)$ of all functions mapping an element of any arbitrary set $X$ to some vector space $V$ with the usual definition of addition and scalar multiplication on functions, should I already know the basis for that vector space?
I tried to extend the notion of the basis of the vector space of linear maps $F(X,F)$ from some set $X={a_0,...,a_n}$ to an arbitrary field where the basis was made up of functions defined as $f_i(a_j)=1$ when $i=j$ and $0$ otherwise. However I have had no such luck developing the idea for $F(X,V)$.
linear-algebra vector-spaces hamel-basis
$endgroup$
How would I go about determining the basis for the vector space $F(X,V)$ of all functions mapping an element of any arbitrary set $X$ to some vector space $V$ with the usual definition of addition and scalar multiplication on functions, should I already know the basis for that vector space?
I tried to extend the notion of the basis of the vector space of linear maps $F(X,F)$ from some set $X={a_0,...,a_n}$ to an arbitrary field where the basis was made up of functions defined as $f_i(a_j)=1$ when $i=j$ and $0$ otherwise. However I have had no such luck developing the idea for $F(X,V)$.
linear-algebra vector-spaces hamel-basis
linear-algebra vector-spaces hamel-basis
edited Dec 10 '18 at 10:48
José Carlos Santos
158k22126228
158k22126228
asked Dec 8 '17 at 15:00
Michael ConnorMichael Connor
404212
404212
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Here's an answer, assuming that $V$ is finite-dimensional. Let $B$ be a basis of $V$. For each $xin X$ and each $win B$, let $f_{x,w}in F(X,V)$ be the function defined by$$f_{x,w}(y)=begin{cases}w&text{ if }y=x\0&text{ otherwise.}end{cases}$$Then ${f_{x,w},|,xin Xwedge win B}$ is a basis of $F(X,V)$.
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This does'nt work if $X$ is infinite : for example a non-zero constant function can't be obtained as a finite linear combination of $f_{x,w}$, as it would be zero for some $y$. This is also true for the case $V=F$ mentioned in the OP.
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– Arnaud D.
Dec 8 '17 at 15:30
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1 Answer
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1 Answer
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$begingroup$
Here's an answer, assuming that $V$ is finite-dimensional. Let $B$ be a basis of $V$. For each $xin X$ and each $win B$, let $f_{x,w}in F(X,V)$ be the function defined by$$f_{x,w}(y)=begin{cases}w&text{ if }y=x\0&text{ otherwise.}end{cases}$$Then ${f_{x,w},|,xin Xwedge win B}$ is a basis of $F(X,V)$.
$endgroup$
$begingroup$
This does'nt work if $X$ is infinite : for example a non-zero constant function can't be obtained as a finite linear combination of $f_{x,w}$, as it would be zero for some $y$. This is also true for the case $V=F$ mentioned in the OP.
$endgroup$
– Arnaud D.
Dec 8 '17 at 15:30
add a comment |
$begingroup$
Here's an answer, assuming that $V$ is finite-dimensional. Let $B$ be a basis of $V$. For each $xin X$ and each $win B$, let $f_{x,w}in F(X,V)$ be the function defined by$$f_{x,w}(y)=begin{cases}w&text{ if }y=x\0&text{ otherwise.}end{cases}$$Then ${f_{x,w},|,xin Xwedge win B}$ is a basis of $F(X,V)$.
$endgroup$
$begingroup$
This does'nt work if $X$ is infinite : for example a non-zero constant function can't be obtained as a finite linear combination of $f_{x,w}$, as it would be zero for some $y$. This is also true for the case $V=F$ mentioned in the OP.
$endgroup$
– Arnaud D.
Dec 8 '17 at 15:30
add a comment |
$begingroup$
Here's an answer, assuming that $V$ is finite-dimensional. Let $B$ be a basis of $V$. For each $xin X$ and each $win B$, let $f_{x,w}in F(X,V)$ be the function defined by$$f_{x,w}(y)=begin{cases}w&text{ if }y=x\0&text{ otherwise.}end{cases}$$Then ${f_{x,w},|,xin Xwedge win B}$ is a basis of $F(X,V)$.
$endgroup$
Here's an answer, assuming that $V$ is finite-dimensional. Let $B$ be a basis of $V$. For each $xin X$ and each $win B$, let $f_{x,w}in F(X,V)$ be the function defined by$$f_{x,w}(y)=begin{cases}w&text{ if }y=x\0&text{ otherwise.}end{cases}$$Then ${f_{x,w},|,xin Xwedge win B}$ is a basis of $F(X,V)$.
answered Dec 8 '17 at 15:06
José Carlos SantosJosé Carlos Santos
158k22126228
158k22126228
$begingroup$
This does'nt work if $X$ is infinite : for example a non-zero constant function can't be obtained as a finite linear combination of $f_{x,w}$, as it would be zero for some $y$. This is also true for the case $V=F$ mentioned in the OP.
$endgroup$
– Arnaud D.
Dec 8 '17 at 15:30
add a comment |
$begingroup$
This does'nt work if $X$ is infinite : for example a non-zero constant function can't be obtained as a finite linear combination of $f_{x,w}$, as it would be zero for some $y$. This is also true for the case $V=F$ mentioned in the OP.
$endgroup$
– Arnaud D.
Dec 8 '17 at 15:30
$begingroup$
This does'nt work if $X$ is infinite : for example a non-zero constant function can't be obtained as a finite linear combination of $f_{x,w}$, as it would be zero for some $y$. This is also true for the case $V=F$ mentioned in the OP.
$endgroup$
– Arnaud D.
Dec 8 '17 at 15:30
$begingroup$
This does'nt work if $X$ is infinite : for example a non-zero constant function can't be obtained as a finite linear combination of $f_{x,w}$, as it would be zero for some $y$. This is also true for the case $V=F$ mentioned in the OP.
$endgroup$
– Arnaud D.
Dec 8 '17 at 15:30
add a comment |
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