Set notation what does the bar symbol mean?
In set notation could somebody explain the meaning of $mid$ in the equation below please? How does it read?
I read it as $s$ and $j$ are an element of $E$ but what does the $j mid$ mean?

Similarly in this equation what does the comma mean?

elementary-set-theory notation
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cherry aldi is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
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add a comment |
In set notation could somebody explain the meaning of $mid$ in the equation below please? How does it read?
I read it as $s$ and $j$ are an element of $E$ but what does the $j mid$ mean?

Similarly in this equation what does the comma mean?

elementary-set-theory notation
New contributor
cherry aldi is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
3
Short answer: such that. Respectively, $j$ such that the ordered pair $(j,i)$ is in $E$, $j$ such that the ordered pair $(s,j)$ is in $E$.
– Steven Wagter
Dec 26 at 12:48
2
See Set-builder notation.
– Mauro ALLEGRANZA
Dec 26 at 12:53
1
@StevenWagter: You should post your comment as an answer. (And explain why commas are used, and often omitted, in lists.)
– John Bentin
Dec 26 at 13:03
add a comment |
In set notation could somebody explain the meaning of $mid$ in the equation below please? How does it read?
I read it as $s$ and $j$ are an element of $E$ but what does the $j mid$ mean?

Similarly in this equation what does the comma mean?

elementary-set-theory notation
New contributor
cherry aldi is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
In set notation could somebody explain the meaning of $mid$ in the equation below please? How does it read?
I read it as $s$ and $j$ are an element of $E$ but what does the $j mid$ mean?

Similarly in this equation what does the comma mean?

elementary-set-theory notation
elementary-set-theory notation
New contributor
cherry aldi is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
cherry aldi is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
edited Dec 26 at 12:53
Mauro ALLEGRANZA
64.2k448112
64.2k448112
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cherry aldi is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
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asked Dec 26 at 12:45
cherry aldi
132
132
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cherry aldi is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
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New contributor
cherry aldi is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
cherry aldi is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
3
Short answer: such that. Respectively, $j$ such that the ordered pair $(j,i)$ is in $E$, $j$ such that the ordered pair $(s,j)$ is in $E$.
– Steven Wagter
Dec 26 at 12:48
2
See Set-builder notation.
– Mauro ALLEGRANZA
Dec 26 at 12:53
1
@StevenWagter: You should post your comment as an answer. (And explain why commas are used, and often omitted, in lists.)
– John Bentin
Dec 26 at 13:03
add a comment |
3
Short answer: such that. Respectively, $j$ such that the ordered pair $(j,i)$ is in $E$, $j$ such that the ordered pair $(s,j)$ is in $E$.
– Steven Wagter
Dec 26 at 12:48
2
See Set-builder notation.
– Mauro ALLEGRANZA
Dec 26 at 12:53
1
@StevenWagter: You should post your comment as an answer. (And explain why commas are used, and often omitted, in lists.)
– John Bentin
Dec 26 at 13:03
3
3
Short answer: such that. Respectively, $j$ such that the ordered pair $(j,i)$ is in $E$, $j$ such that the ordered pair $(s,j)$ is in $E$.
– Steven Wagter
Dec 26 at 12:48
Short answer: such that. Respectively, $j$ such that the ordered pair $(j,i)$ is in $E$, $j$ such that the ordered pair $(s,j)$ is in $E$.
– Steven Wagter
Dec 26 at 12:48
2
2
See Set-builder notation.
– Mauro ALLEGRANZA
Dec 26 at 12:53
See Set-builder notation.
– Mauro ALLEGRANZA
Dec 26 at 12:53
1
1
@StevenWagter: You should post your comment as an answer. (And explain why commas are used, and often omitted, in lists.)
– John Bentin
Dec 26 at 13:03
@StevenWagter: You should post your comment as an answer. (And explain why commas are used, and often omitted, in lists.)
– John Bentin
Dec 26 at 13:03
add a comment |
1 Answer
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active
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Suppose the $m_{j,i}$'s are elements of the set $M$, and that each pair $(j,i) subset I subset Bbb{N}^2$ is an index of an element in $M$, where $I$ is an indexing set. Then
$$Inputs(i) = sum_{j|(j,i) in E} m_{j,i}$$ means "Given some fixed input value $i$, sum those elements in $M$ whose index $(j,i)$ satisfies $(j,i) in E$.
Here $E$ is some subset of $Bbb{N}^2$. So we loop over all the $j$'s ($i$ is fixed) and add the terms corresponding to those $j$'s which satisfy $(j,i) in E$.
In the second picture, the comma can be read as a vertical bar. They have the same meaning in this case.
EDIT - in response to Shaun:
$I$ is some set used for indexing the elements in $M$, which must exist since otherwise the subscript of ordered pairs doesn't make sense. For example, take a $2times2$-matrix. Then if you want to take the matrix element of the first row, second column, one writes $a_{1,2}$. But what is really going on, is that you have the index set $I = { (1,1),(1,2),(2,1),(2,2)}$, where there is a one-to-one correspondence between elements in $I$ and the set of matrix elements.
For example, returning to our situation, taking the same indexing set $I$ as above and letting $E = {(1,1),(2,1),(2,2)}$, then $Inputs(2) = m_{2,2}$.
Another example of indexing sets: $$1/2+1/4+1/8 +... = sum_{n in Bbb{N} } frac{1}{2^n}$$
Here $Bbb{N}$ is the indexing set.
Where did the $I$ come from? Don't you mean $E$?
– Shaun
2 days ago
1
@Shaun added some clarification, does it make more sense now?
– Steven Wagter
2 days ago
Yes. Thank you, @StevenWagter :)
– Shaun
2 days ago
add a comment |
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Suppose the $m_{j,i}$'s are elements of the set $M$, and that each pair $(j,i) subset I subset Bbb{N}^2$ is an index of an element in $M$, where $I$ is an indexing set. Then
$$Inputs(i) = sum_{j|(j,i) in E} m_{j,i}$$ means "Given some fixed input value $i$, sum those elements in $M$ whose index $(j,i)$ satisfies $(j,i) in E$.
Here $E$ is some subset of $Bbb{N}^2$. So we loop over all the $j$'s ($i$ is fixed) and add the terms corresponding to those $j$'s which satisfy $(j,i) in E$.
In the second picture, the comma can be read as a vertical bar. They have the same meaning in this case.
EDIT - in response to Shaun:
$I$ is some set used for indexing the elements in $M$, which must exist since otherwise the subscript of ordered pairs doesn't make sense. For example, take a $2times2$-matrix. Then if you want to take the matrix element of the first row, second column, one writes $a_{1,2}$. But what is really going on, is that you have the index set $I = { (1,1),(1,2),(2,1),(2,2)}$, where there is a one-to-one correspondence between elements in $I$ and the set of matrix elements.
For example, returning to our situation, taking the same indexing set $I$ as above and letting $E = {(1,1),(2,1),(2,2)}$, then $Inputs(2) = m_{2,2}$.
Another example of indexing sets: $$1/2+1/4+1/8 +... = sum_{n in Bbb{N} } frac{1}{2^n}$$
Here $Bbb{N}$ is the indexing set.
Where did the $I$ come from? Don't you mean $E$?
– Shaun
2 days ago
1
@Shaun added some clarification, does it make more sense now?
– Steven Wagter
2 days ago
Yes. Thank you, @StevenWagter :)
– Shaun
2 days ago
add a comment |
Suppose the $m_{j,i}$'s are elements of the set $M$, and that each pair $(j,i) subset I subset Bbb{N}^2$ is an index of an element in $M$, where $I$ is an indexing set. Then
$$Inputs(i) = sum_{j|(j,i) in E} m_{j,i}$$ means "Given some fixed input value $i$, sum those elements in $M$ whose index $(j,i)$ satisfies $(j,i) in E$.
Here $E$ is some subset of $Bbb{N}^2$. So we loop over all the $j$'s ($i$ is fixed) and add the terms corresponding to those $j$'s which satisfy $(j,i) in E$.
In the second picture, the comma can be read as a vertical bar. They have the same meaning in this case.
EDIT - in response to Shaun:
$I$ is some set used for indexing the elements in $M$, which must exist since otherwise the subscript of ordered pairs doesn't make sense. For example, take a $2times2$-matrix. Then if you want to take the matrix element of the first row, second column, one writes $a_{1,2}$. But what is really going on, is that you have the index set $I = { (1,1),(1,2),(2,1),(2,2)}$, where there is a one-to-one correspondence between elements in $I$ and the set of matrix elements.
For example, returning to our situation, taking the same indexing set $I$ as above and letting $E = {(1,1),(2,1),(2,2)}$, then $Inputs(2) = m_{2,2}$.
Another example of indexing sets: $$1/2+1/4+1/8 +... = sum_{n in Bbb{N} } frac{1}{2^n}$$
Here $Bbb{N}$ is the indexing set.
Where did the $I$ come from? Don't you mean $E$?
– Shaun
2 days ago
1
@Shaun added some clarification, does it make more sense now?
– Steven Wagter
2 days ago
Yes. Thank you, @StevenWagter :)
– Shaun
2 days ago
add a comment |
Suppose the $m_{j,i}$'s are elements of the set $M$, and that each pair $(j,i) subset I subset Bbb{N}^2$ is an index of an element in $M$, where $I$ is an indexing set. Then
$$Inputs(i) = sum_{j|(j,i) in E} m_{j,i}$$ means "Given some fixed input value $i$, sum those elements in $M$ whose index $(j,i)$ satisfies $(j,i) in E$.
Here $E$ is some subset of $Bbb{N}^2$. So we loop over all the $j$'s ($i$ is fixed) and add the terms corresponding to those $j$'s which satisfy $(j,i) in E$.
In the second picture, the comma can be read as a vertical bar. They have the same meaning in this case.
EDIT - in response to Shaun:
$I$ is some set used for indexing the elements in $M$, which must exist since otherwise the subscript of ordered pairs doesn't make sense. For example, take a $2times2$-matrix. Then if you want to take the matrix element of the first row, second column, one writes $a_{1,2}$. But what is really going on, is that you have the index set $I = { (1,1),(1,2),(2,1),(2,2)}$, where there is a one-to-one correspondence between elements in $I$ and the set of matrix elements.
For example, returning to our situation, taking the same indexing set $I$ as above and letting $E = {(1,1),(2,1),(2,2)}$, then $Inputs(2) = m_{2,2}$.
Another example of indexing sets: $$1/2+1/4+1/8 +... = sum_{n in Bbb{N} } frac{1}{2^n}$$
Here $Bbb{N}$ is the indexing set.
Suppose the $m_{j,i}$'s are elements of the set $M$, and that each pair $(j,i) subset I subset Bbb{N}^2$ is an index of an element in $M$, where $I$ is an indexing set. Then
$$Inputs(i) = sum_{j|(j,i) in E} m_{j,i}$$ means "Given some fixed input value $i$, sum those elements in $M$ whose index $(j,i)$ satisfies $(j,i) in E$.
Here $E$ is some subset of $Bbb{N}^2$. So we loop over all the $j$'s ($i$ is fixed) and add the terms corresponding to those $j$'s which satisfy $(j,i) in E$.
In the second picture, the comma can be read as a vertical bar. They have the same meaning in this case.
EDIT - in response to Shaun:
$I$ is some set used for indexing the elements in $M$, which must exist since otherwise the subscript of ordered pairs doesn't make sense. For example, take a $2times2$-matrix. Then if you want to take the matrix element of the first row, second column, one writes $a_{1,2}$. But what is really going on, is that you have the index set $I = { (1,1),(1,2),(2,1),(2,2)}$, where there is a one-to-one correspondence between elements in $I$ and the set of matrix elements.
For example, returning to our situation, taking the same indexing set $I$ as above and letting $E = {(1,1),(2,1),(2,2)}$, then $Inputs(2) = m_{2,2}$.
Another example of indexing sets: $$1/2+1/4+1/8 +... = sum_{n in Bbb{N} } frac{1}{2^n}$$
Here $Bbb{N}$ is the indexing set.
edited 2 days ago
answered Dec 26 at 13:34
Steven Wagter
1178
1178
Where did the $I$ come from? Don't you mean $E$?
– Shaun
2 days ago
1
@Shaun added some clarification, does it make more sense now?
– Steven Wagter
2 days ago
Yes. Thank you, @StevenWagter :)
– Shaun
2 days ago
add a comment |
Where did the $I$ come from? Don't you mean $E$?
– Shaun
2 days ago
1
@Shaun added some clarification, does it make more sense now?
– Steven Wagter
2 days ago
Yes. Thank you, @StevenWagter :)
– Shaun
2 days ago
Where did the $I$ come from? Don't you mean $E$?
– Shaun
2 days ago
Where did the $I$ come from? Don't you mean $E$?
– Shaun
2 days ago
1
1
@Shaun added some clarification, does it make more sense now?
– Steven Wagter
2 days ago
@Shaun added some clarification, does it make more sense now?
– Steven Wagter
2 days ago
Yes. Thank you, @StevenWagter :)
– Shaun
2 days ago
Yes. Thank you, @StevenWagter :)
– Shaun
2 days ago
add a comment |
cherry aldi is a new contributor. Be nice, and check out our Code of Conduct.
cherry aldi is a new contributor. Be nice, and check out our Code of Conduct.
cherry aldi is a new contributor. Be nice, and check out our Code of Conduct.
cherry aldi is a new contributor. Be nice, and check out our Code of Conduct.
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3
Short answer: such that. Respectively, $j$ such that the ordered pair $(j,i)$ is in $E$, $j$ such that the ordered pair $(s,j)$ is in $E$.
– Steven Wagter
Dec 26 at 12:48
2
See Set-builder notation.
– Mauro ALLEGRANZA
Dec 26 at 12:53
1
@StevenWagter: You should post your comment as an answer. (And explain why commas are used, and often omitted, in lists.)
– John Bentin
Dec 26 at 13:03