Notation for subset of a set $A$ that is disjoint with every other set but $A$
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I have found myself making my own notation when considering several sets, say $A,B,C,D,E$, and wanting to denote for example the set $A^triangle = x: xin A land xnotin Y, Yneq X$. I know when considering just two sets like $A$ and $B$ I could write the somewhat more inconvenient $Asetminus B$, but I don't know how to conveniently write this when considering several sets. Is there a simple notation for $A^triangle$?
edit: Maybe I expressed myself unclearly. Although I appreciate the help, I don't consider $Asetminus(Bcup C cup D cup E)$ a simple way of writing $A^triangle$. It becomes very unpractical when having to write it over and over again, not to speak of when considering more sets than five. I'm looking for something similar to $A^triangle$, preferably just one small extra symbol denoting the set. Similar to how $barA$ can denote the complement of $A$. Again, sorry for not making this clear enough.
elementary-set-theory
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up vote
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I have found myself making my own notation when considering several sets, say $A,B,C,D,E$, and wanting to denote for example the set $A^triangle = x: xin A land xnotin Y, Yneq X$. I know when considering just two sets like $A$ and $B$ I could write the somewhat more inconvenient $Asetminus B$, but I don't know how to conveniently write this when considering several sets. Is there a simple notation for $A^triangle$?
edit: Maybe I expressed myself unclearly. Although I appreciate the help, I don't consider $Asetminus(Bcup C cup D cup E)$ a simple way of writing $A^triangle$. It becomes very unpractical when having to write it over and over again, not to speak of when considering more sets than five. I'm looking for something similar to $A^triangle$, preferably just one small extra symbol denoting the set. Similar to how $barA$ can denote the complement of $A$. Again, sorry for not making this clear enough.
elementary-set-theory
3
Would $A setminus (B cup C cup D cup E)$ work?
â Evan Chen
Aug 26 at 21:31
@EvanChen I'm afraid I expressed myself a bit unlcearly, I don't find that notation simple or convenient. I thought it was clear by me bringing up the example $Asetminus B$. But thank you for your help.
â DancingIceCream
Aug 27 at 5:17
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up vote
4
down vote
favorite
up vote
4
down vote
favorite
I have found myself making my own notation when considering several sets, say $A,B,C,D,E$, and wanting to denote for example the set $A^triangle = x: xin A land xnotin Y, Yneq X$. I know when considering just two sets like $A$ and $B$ I could write the somewhat more inconvenient $Asetminus B$, but I don't know how to conveniently write this when considering several sets. Is there a simple notation for $A^triangle$?
edit: Maybe I expressed myself unclearly. Although I appreciate the help, I don't consider $Asetminus(Bcup C cup D cup E)$ a simple way of writing $A^triangle$. It becomes very unpractical when having to write it over and over again, not to speak of when considering more sets than five. I'm looking for something similar to $A^triangle$, preferably just one small extra symbol denoting the set. Similar to how $barA$ can denote the complement of $A$. Again, sorry for not making this clear enough.
elementary-set-theory
I have found myself making my own notation when considering several sets, say $A,B,C,D,E$, and wanting to denote for example the set $A^triangle = x: xin A land xnotin Y, Yneq X$. I know when considering just two sets like $A$ and $B$ I could write the somewhat more inconvenient $Asetminus B$, but I don't know how to conveniently write this when considering several sets. Is there a simple notation for $A^triangle$?
edit: Maybe I expressed myself unclearly. Although I appreciate the help, I don't consider $Asetminus(Bcup C cup D cup E)$ a simple way of writing $A^triangle$. It becomes very unpractical when having to write it over and over again, not to speak of when considering more sets than five. I'm looking for something similar to $A^triangle$, preferably just one small extra symbol denoting the set. Similar to how $barA$ can denote the complement of $A$. Again, sorry for not making this clear enough.
elementary-set-theory
edited Aug 27 at 5:53
asked Aug 26 at 20:36
DancingIceCream
385
385
3
Would $A setminus (B cup C cup D cup E)$ work?
â Evan Chen
Aug 26 at 21:31
@EvanChen I'm afraid I expressed myself a bit unlcearly, I don't find that notation simple or convenient. I thought it was clear by me bringing up the example $Asetminus B$. But thank you for your help.
â DancingIceCream
Aug 27 at 5:17
add a comment |Â
3
Would $A setminus (B cup C cup D cup E)$ work?
â Evan Chen
Aug 26 at 21:31
@EvanChen I'm afraid I expressed myself a bit unlcearly, I don't find that notation simple or convenient. I thought it was clear by me bringing up the example $Asetminus B$. But thank you for your help.
â DancingIceCream
Aug 27 at 5:17
3
3
Would $A setminus (B cup C cup D cup E)$ work?
â Evan Chen
Aug 26 at 21:31
Would $A setminus (B cup C cup D cup E)$ work?
â Evan Chen
Aug 26 at 21:31
@EvanChen I'm afraid I expressed myself a bit unlcearly, I don't find that notation simple or convenient. I thought it was clear by me bringing up the example $Asetminus B$. But thank you for your help.
â DancingIceCream
Aug 27 at 5:17
@EvanChen I'm afraid I expressed myself a bit unlcearly, I don't find that notation simple or convenient. I thought it was clear by me bringing up the example $Asetminus B$. But thank you for your help.
â DancingIceCream
Aug 27 at 5:17
add a comment |Â
2 Answers
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You can find out that $x in A^â³Leftrightarrow (x in A â§x notin B â§x notin Câ§x notin Dâ§x notin E)$.
Hence, by de Morgan law, $$x in A^â³Leftrightarrow (x in A â§neg (x in B vee x in Cvee x in Dvee x in E))$$$$Leftrightarrow (x in A â§neg (x in Bcup Ccup D cup E ))$$$$Leftrightarrow (x in Asetminus( Bcup Ccup D cup E ))$$
Therefore, $Asetminus( Bcup Ccup D cup E )$ is what you are looking for.
add a comment |Â
up vote
0
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We have already standard notations of difference and union that cover your wanted new notation.
If your set is only non-disjoint with $A$ and disjoint with some family of sets $F$ we could do some shortcuts and write (if B is designation of that set) that as $(B cap A neq emptyset) land (B cap (bigcup F) = emptyset) $
We could write that also as $displaystyle bigcap_B (A,F)=( supset emptyset , = emptyset) $
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2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
0
down vote
You can find out that $x in A^â³Leftrightarrow (x in A â§x notin B â§x notin Câ§x notin Dâ§x notin E)$.
Hence, by de Morgan law, $$x in A^â³Leftrightarrow (x in A â§neg (x in B vee x in Cvee x in Dvee x in E))$$$$Leftrightarrow (x in A â§neg (x in Bcup Ccup D cup E ))$$$$Leftrightarrow (x in Asetminus( Bcup Ccup D cup E ))$$
Therefore, $Asetminus( Bcup Ccup D cup E )$ is what you are looking for.
add a comment |Â
up vote
0
down vote
You can find out that $x in A^â³Leftrightarrow (x in A â§x notin B â§x notin Câ§x notin Dâ§x notin E)$.
Hence, by de Morgan law, $$x in A^â³Leftrightarrow (x in A â§neg (x in B vee x in Cvee x in Dvee x in E))$$$$Leftrightarrow (x in A â§neg (x in Bcup Ccup D cup E ))$$$$Leftrightarrow (x in Asetminus( Bcup Ccup D cup E ))$$
Therefore, $Asetminus( Bcup Ccup D cup E )$ is what you are looking for.
add a comment |Â
up vote
0
down vote
up vote
0
down vote
You can find out that $x in A^â³Leftrightarrow (x in A â§x notin B â§x notin Câ§x notin Dâ§x notin E)$.
Hence, by de Morgan law, $$x in A^â³Leftrightarrow (x in A â§neg (x in B vee x in Cvee x in Dvee x in E))$$$$Leftrightarrow (x in A â§neg (x in Bcup Ccup D cup E ))$$$$Leftrightarrow (x in Asetminus( Bcup Ccup D cup E ))$$
Therefore, $Asetminus( Bcup Ccup D cup E )$ is what you are looking for.
You can find out that $x in A^â³Leftrightarrow (x in A â§x notin B â§x notin Câ§x notin Dâ§x notin E)$.
Hence, by de Morgan law, $$x in A^â³Leftrightarrow (x in A â§neg (x in B vee x in Cvee x in Dvee x in E))$$$$Leftrightarrow (x in A â§neg (x in Bcup Ccup D cup E ))$$$$Leftrightarrow (x in Asetminus( Bcup Ccup D cup E ))$$
Therefore, $Asetminus( Bcup Ccup D cup E )$ is what you are looking for.
answered Aug 27 at 0:13
Steve Cheng éÂÂå®Âå¼Â
236
236
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add a comment |Â
up vote
0
down vote
We have already standard notations of difference and union that cover your wanted new notation.
If your set is only non-disjoint with $A$ and disjoint with some family of sets $F$ we could do some shortcuts and write (if B is designation of that set) that as $(B cap A neq emptyset) land (B cap (bigcup F) = emptyset) $
We could write that also as $displaystyle bigcap_B (A,F)=( supset emptyset , = emptyset) $
add a comment |Â
up vote
0
down vote
We have already standard notations of difference and union that cover your wanted new notation.
If your set is only non-disjoint with $A$ and disjoint with some family of sets $F$ we could do some shortcuts and write (if B is designation of that set) that as $(B cap A neq emptyset) land (B cap (bigcup F) = emptyset) $
We could write that also as $displaystyle bigcap_B (A,F)=( supset emptyset , = emptyset) $
add a comment |Â
up vote
0
down vote
up vote
0
down vote
We have already standard notations of difference and union that cover your wanted new notation.
If your set is only non-disjoint with $A$ and disjoint with some family of sets $F$ we could do some shortcuts and write (if B is designation of that set) that as $(B cap A neq emptyset) land (B cap (bigcup F) = emptyset) $
We could write that also as $displaystyle bigcap_B (A,F)=( supset emptyset , = emptyset) $
We have already standard notations of difference and union that cover your wanted new notation.
If your set is only non-disjoint with $A$ and disjoint with some family of sets $F$ we could do some shortcuts and write (if B is designation of that set) that as $(B cap A neq emptyset) land (B cap (bigcup F) = emptyset) $
We could write that also as $displaystyle bigcap_B (A,F)=( supset emptyset , = emptyset) $
answered Aug 27 at 5:47
Right
1,046213
1,046213
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3
Would $A setminus (B cup C cup D cup E)$ work?
â Evan Chen
Aug 26 at 21:31
@EvanChen I'm afraid I expressed myself a bit unlcearly, I don't find that notation simple or convenient. I thought it was clear by me bringing up the example $Asetminus B$. But thank you for your help.
â DancingIceCream
Aug 27 at 5:17