Question about math symbol $bigsqcup$
Can someone tell me what this symbol means?
$bigsqcup$
notation
asked Aug 3 '12 at 18:42
WacDonald's
2601511
|
show 3 more comments
Can someone tell me what this symbol means?
$bigsqcup$
notation
asked Aug 3 '12 at 18:42
WacDonald's
2601511
13
It would be extremely helpful if you tell us where you saw it. This is like asking what does the symbol $partial$ means. It may have different meanings in different contexts.
– Asaf Karagila♦
Aug 3 '12 at 18:43
3
It's usually some generalization or specialization of the "union" sign, but it does greatly depend on context.
– Thomas Andrews
Aug 3 '12 at 18:44
13
My default interpretation is of disjoint union, thought it's also similar to the symbol often used coproducts.
– Andrew
Aug 3 '12 at 18:44
3
Search results forbigsqcupon math.SE.
– user2468
Aug 3 '12 at 18:52
8
I think it tells you where to put the staple.
– Gerry Myerson
Aug 3 '12 at 23:29
|
show 3 more comments
Can someone tell me what this symbol means?
$bigsqcup$
notation
asked Aug 3 '12 at 18:42
WacDonald's
2601511
Can someone tell me what this symbol means?
$bigsqcup$
notation
notation
asked Aug 3 '12 at 18:42
WacDonald's
2601511
asked Aug 3 '12 at 18:42
WacDonald's
2601511
asked Aug 3 '12 at 18:42
WacDonald's
2601511
asked Aug 3 '12 at 18:42
WacDonald's
2601511
asked Aug 3 '12 at 18:42
WacDonald's
2601511
2601511
13
It would be extremely helpful if you tell us where you saw it. This is like asking what does the symbol $partial$ means. It may have different meanings in different contexts.
– Asaf Karagila♦
Aug 3 '12 at 18:43
3
It's usually some generalization or specialization of the "union" sign, but it does greatly depend on context.
– Thomas Andrews
Aug 3 '12 at 18:44
13
My default interpretation is of disjoint union, thought it's also similar to the symbol often used coproducts.
– Andrew
Aug 3 '12 at 18:44
3
Search results forbigsqcupon math.SE.
– user2468
Aug 3 '12 at 18:52
8
I think it tells you where to put the staple.
– Gerry Myerson
Aug 3 '12 at 23:29
|
show 3 more comments
13
It would be extremely helpful if you tell us where you saw it. This is like asking what does the symbol $partial$ means. It may have different meanings in different contexts.
– Asaf Karagila♦
Aug 3 '12 at 18:43
3
It's usually some generalization or specialization of the "union" sign, but it does greatly depend on context.
– Thomas Andrews
Aug 3 '12 at 18:44
13
My default interpretation is of disjoint union, thought it's also similar to the symbol often used coproducts.
– Andrew
Aug 3 '12 at 18:44
3
Search results forbigsqcupon math.SE.
– user2468
Aug 3 '12 at 18:52
8
I think it tells you where to put the staple.
– Gerry Myerson
Aug 3 '12 at 23:29
13
13
It would be extremely helpful if you tell us where you saw it. This is like asking what does the symbol $partial$ means. It may have different meanings in different contexts.
– Asaf Karagila♦
Aug 3 '12 at 18:43
It would be extremely helpful if you tell us where you saw it. This is like asking what does the symbol $partial$ means. It may have different meanings in different contexts.
– Asaf Karagila♦
Aug 3 '12 at 18:43
3
3
It's usually some generalization or specialization of the "union" sign, but it does greatly depend on context.
– Thomas Andrews
Aug 3 '12 at 18:44
It's usually some generalization or specialization of the "union" sign, but it does greatly depend on context.
– Thomas Andrews
Aug 3 '12 at 18:44
13
13
My default interpretation is of disjoint union, thought it's also similar to the symbol often used coproducts.
– Andrew
Aug 3 '12 at 18:44
My default interpretation is of disjoint union, thought it's also similar to the symbol often used coproducts.
– Andrew
Aug 3 '12 at 18:44
3
3
Search results for
bigsqcup on math.SE.– user2468
Aug 3 '12 at 18:52
Search results for
bigsqcup on math.SE.– user2468
Aug 3 '12 at 18:52
8
8
I think it tells you where to put the staple.
– Gerry Myerson
Aug 3 '12 at 23:29
I think it tells you where to put the staple.
– Gerry Myerson
Aug 3 '12 at 23:29
|
show 3 more comments
2 Answers
2
active
oldest
votes
It is the disjoint union symbol- it is most commonly used informally to denote situations where you take the union of two disjoint sets. The actual definition though is more of a tagged union- intuitively, you index the sets to be unioned by some set $I$, and then the result is the collection of all the elements of each set, along with a "tag" that says which set it came from.
In your case, formally you have sets $A$ and $B$- let's re-label these $A_1$ and $A_2$. The disjoint union is $A_1 bigsqcup A_2 ={ (a,1) vert ain A_1} cup { (a,2) vert ain A_2}$. So if they have some element $a$ in common, you end up with both $(a,1)$ and $(a,2)$ in your disjoint union. In the case that they have no common elements, the result is the same as the standard union.
edited Jan 3 at 19:09
Ben
1478
answered Aug 4 '12 at 4:59
Devlin Mallory
1,7631016
add a comment |
$Abigsqcup B$ means that the sets are a "disjoint" union
answered Aug 4 '12 at 2:39
i. m. soloveichik
3,70511125
2
Does this mean $Acap B=emptyset$?
– Jorge Fernández
Aug 4 '12 at 2:57
@Khromonkey : No, not always. See Devlin Mallory's response above.
– KReiser
Aug 4 '12 at 5:18
@Khromonkey Yes
– i. m. soloveichik
Aug 4 '12 at 12:31
add a comment |
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2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
It is the disjoint union symbol- it is most commonly used informally to denote situations where you take the union of two disjoint sets. The actual definition though is more of a tagged union- intuitively, you index the sets to be unioned by some set $I$, and then the result is the collection of all the elements of each set, along with a "tag" that says which set it came from.
In your case, formally you have sets $A$ and $B$- let's re-label these $A_1$ and $A_2$. The disjoint union is $A_1 bigsqcup A_2 ={ (a,1) vert ain A_1} cup { (a,2) vert ain A_2}$. So if they have some element $a$ in common, you end up with both $(a,1)$ and $(a,2)$ in your disjoint union. In the case that they have no common elements, the result is the same as the standard union.
edited Jan 3 at 19:09
Ben
1478
answered Aug 4 '12 at 4:59
Devlin Mallory
1,7631016
add a comment |
It is the disjoint union symbol- it is most commonly used informally to denote situations where you take the union of two disjoint sets. The actual definition though is more of a tagged union- intuitively, you index the sets to be unioned by some set $I$, and then the result is the collection of all the elements of each set, along with a "tag" that says which set it came from.
In your case, formally you have sets $A$ and $B$- let's re-label these $A_1$ and $A_2$. The disjoint union is $A_1 bigsqcup A_2 ={ (a,1) vert ain A_1} cup { (a,2) vert ain A_2}$. So if they have some element $a$ in common, you end up with both $(a,1)$ and $(a,2)$ in your disjoint union. In the case that they have no common elements, the result is the same as the standard union.
edited Jan 3 at 19:09
Ben
1478
answered Aug 4 '12 at 4:59
Devlin Mallory
1,7631016
add a comment |
It is the disjoint union symbol- it is most commonly used informally to denote situations where you take the union of two disjoint sets. The actual definition though is more of a tagged union- intuitively, you index the sets to be unioned by some set $I$, and then the result is the collection of all the elements of each set, along with a "tag" that says which set it came from.
In your case, formally you have sets $A$ and $B$- let's re-label these $A_1$ and $A_2$. The disjoint union is $A_1 bigsqcup A_2 ={ (a,1) vert ain A_1} cup { (a,2) vert ain A_2}$. So if they have some element $a$ in common, you end up with both $(a,1)$ and $(a,2)$ in your disjoint union. In the case that they have no common elements, the result is the same as the standard union.
edited Jan 3 at 19:09
Ben
1478
answered Aug 4 '12 at 4:59
Devlin Mallory
1,7631016
It is the disjoint union symbol- it is most commonly used informally to denote situations where you take the union of two disjoint sets. The actual definition though is more of a tagged union- intuitively, you index the sets to be unioned by some set $I$, and then the result is the collection of all the elements of each set, along with a "tag" that says which set it came from.
In your case, formally you have sets $A$ and $B$- let's re-label these $A_1$ and $A_2$. The disjoint union is $A_1 bigsqcup A_2 ={ (a,1) vert ain A_1} cup { (a,2) vert ain A_2}$. So if they have some element $a$ in common, you end up with both $(a,1)$ and $(a,2)$ in your disjoint union. In the case that they have no common elements, the result is the same as the standard union.
edited Jan 3 at 19:09
Ben
1478
answered Aug 4 '12 at 4:59
Devlin Mallory
1,7631016
edited Jan 3 at 19:09
Ben
1478
edited Jan 3 at 19:09
Ben
1478
edited Jan 3 at 19:09
Ben
1478
1478
answered Aug 4 '12 at 4:59
Devlin Mallory
1,7631016
answered Aug 4 '12 at 4:59
Devlin Mallory
1,7631016
answered Aug 4 '12 at 4:59
Devlin Mallory
1,7631016
1,7631016
add a comment |
add a comment |
$Abigsqcup B$ means that the sets are a "disjoint" union
answered Aug 4 '12 at 2:39
i. m. soloveichik
3,70511125
2
Does this mean $Acap B=emptyset$?
– Jorge Fernández
Aug 4 '12 at 2:57
@Khromonkey : No, not always. See Devlin Mallory's response above.
– KReiser
Aug 4 '12 at 5:18
@Khromonkey Yes
– i. m. soloveichik
Aug 4 '12 at 12:31
add a comment |
$Abigsqcup B$ means that the sets are a "disjoint" union
answered Aug 4 '12 at 2:39
i. m. soloveichik
3,70511125
2
Does this mean $Acap B=emptyset$?
– Jorge Fernández
Aug 4 '12 at 2:57
@Khromonkey : No, not always. See Devlin Mallory's response above.
– KReiser
Aug 4 '12 at 5:18
@Khromonkey Yes
– i. m. soloveichik
Aug 4 '12 at 12:31
add a comment |
$Abigsqcup B$ means that the sets are a "disjoint" union
answered Aug 4 '12 at 2:39
i. m. soloveichik
3,70511125
$Abigsqcup B$ means that the sets are a "disjoint" union
answered Aug 4 '12 at 2:39
i. m. soloveichik
3,70511125
answered Aug 4 '12 at 2:39
i. m. soloveichik
3,70511125
answered Aug 4 '12 at 2:39
i. m. soloveichik
3,70511125
answered Aug 4 '12 at 2:39
i. m. soloveichik
3,70511125
3,70511125
2
Does this mean $Acap B=emptyset$?
– Jorge Fernández
Aug 4 '12 at 2:57
@Khromonkey : No, not always. See Devlin Mallory's response above.
– KReiser
Aug 4 '12 at 5:18
@Khromonkey Yes
– i. m. soloveichik
Aug 4 '12 at 12:31
add a comment |
2
Does this mean $Acap B=emptyset$?
– Jorge Fernández
Aug 4 '12 at 2:57
@Khromonkey : No, not always. See Devlin Mallory's response above.
– KReiser
Aug 4 '12 at 5:18
@Khromonkey Yes
– i. m. soloveichik
Aug 4 '12 at 12:31
2
2
Does this mean $Acap B=emptyset$?
– Jorge Fernández
Aug 4 '12 at 2:57
Does this mean $Acap B=emptyset$?
– Jorge Fernández
Aug 4 '12 at 2:57
@Khromonkey : No, not always. See Devlin Mallory's response above.
– KReiser
Aug 4 '12 at 5:18
@Khromonkey : No, not always. See Devlin Mallory's response above.
– KReiser
Aug 4 '12 at 5:18
@Khromonkey Yes
– i. m. soloveichik
Aug 4 '12 at 12:31
@Khromonkey Yes
– i. m. soloveichik
Aug 4 '12 at 12:31
add a comment |
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13
It would be extremely helpful if you tell us where you saw it. This is like asking what does the symbol $partial$ means. It may have different meanings in different contexts.
– Asaf Karagila♦
Aug 3 '12 at 18:43
3
It's usually some generalization or specialization of the "union" sign, but it does greatly depend on context.
– Thomas Andrews
Aug 3 '12 at 18:44
13
My default interpretation is of disjoint union, thought it's also similar to the symbol often used coproducts.
– Andrew
Aug 3 '12 at 18:44
3
Search results for
bigsqcupon math.SE.– user2468
Aug 3 '12 at 18:52
8
I think it tells you where to put the staple.
– Gerry Myerson
Aug 3 '12 at 23:29