What would you call a finite collection of unordered objects that are not necessarily distinct?












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I Just want to know the name for this if there is one because I don't think it satisifies any of the formal definitions for sets, n-tuples, sequences, combinations, permutations, or any other enumerated objects I can think of.



For convenience, I will henceforth use the term $mathbf{ set^*}$ with an asterisk to refer to what I described in the title.



As a quick example, let $mathbf{A}$ and $mathbf{B }$ be $mathbf{ set^*}$'s where $$mathbf{A = {3,3,4,11,4,8}}$$
$$mathbf{B = {4,3,4,8,11,3}}$$



Then $mathbf{A }$ and $mathbf{ B }$ are equal.










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    9












    $begingroup$


    I Just want to know the name for this if there is one because I don't think it satisifies any of the formal definitions for sets, n-tuples, sequences, combinations, permutations, or any other enumerated objects I can think of.



    For convenience, I will henceforth use the term $mathbf{ set^*}$ with an asterisk to refer to what I described in the title.



    As a quick example, let $mathbf{A}$ and $mathbf{B }$ be $mathbf{ set^*}$'s where $$mathbf{A = {3,3,4,11,4,8}}$$
    $$mathbf{B = {4,3,4,8,11,3}}$$



    Then $mathbf{A }$ and $mathbf{ B }$ are equal.










    share|cite|improve this question









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      9












      9








      9


      2



      $begingroup$


      I Just want to know the name for this if there is one because I don't think it satisifies any of the formal definitions for sets, n-tuples, sequences, combinations, permutations, or any other enumerated objects I can think of.



      For convenience, I will henceforth use the term $mathbf{ set^*}$ with an asterisk to refer to what I described in the title.



      As a quick example, let $mathbf{A}$ and $mathbf{B }$ be $mathbf{ set^*}$'s where $$mathbf{A = {3,3,4,11,4,8}}$$
      $$mathbf{B = {4,3,4,8,11,3}}$$



      Then $mathbf{A }$ and $mathbf{ B }$ are equal.










      share|cite|improve this question









      $endgroup$




      I Just want to know the name for this if there is one because I don't think it satisifies any of the formal definitions for sets, n-tuples, sequences, combinations, permutations, or any other enumerated objects I can think of.



      For convenience, I will henceforth use the term $mathbf{ set^*}$ with an asterisk to refer to what I described in the title.



      As a quick example, let $mathbf{A}$ and $mathbf{B }$ be $mathbf{ set^*}$'s where $$mathbf{A = {3,3,4,11,4,8}}$$
      $$mathbf{B = {4,3,4,8,11,3}}$$



      Then $mathbf{A }$ and $mathbf{ B }$ are equal.







      combinatorics elementary-set-theory notation permutations definition






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      asked Mar 25 at 11:20









      Nicholas CousarNicholas Cousar

      374312




      374312






















          4 Answers
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          35












          $begingroup$

          If you're looking for something like a set which may have repeated elements, standard terms are multiset or bag. See multiset on wikipedia.






          share|cite|improve this answer









          $endgroup$





















            7












            $begingroup$

            The common term is multiset. For a formal definition, you can for instance define the set of multisets of size $n$ of a given set $A$ as $A^n/mathfrak{S}_n$ where $mathfrak{S}_n$ acts by permutation of the factors; or if you don't want to be bothered by size you can define it as a map $f: Ato mathbb{N}$ where $f(a)$ is supposed to represent the number of times $a$ appears in the multiset.



            These are two interesting models for different situations, and there are probably more.






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              4












              $begingroup$

              In this context you can identify what you call a $mathbf{ set^*}$ with a function that has a finite domain and has $mathbb N={1,2,3cdots}$ as codomain.



              $A$ and $B$ in your question can both be identified with function: $${langle3,2rangle,langle4,2rangle,langle8,1rangle,langle11,1rangle}$$Domain of the function in this case is the set ${3,4,8,11}$.






              share|cite|improve this answer









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                1












                $begingroup$

                If two objects can be distinguished by the number of times an element appears in them, that is called "multiplicity". So the more mathy version of "finite collection of unordered objects that are not necessarily distinct" would be "unordered finite collection with multiplicity" or "finite collection with multiplicity but not order".



                The single-word term for unordered collections with multiplicity is "multi-set", but I don't think there's any single-word term for finite multi-sets. Googling "math collection multiplicity no order" returns http://mathworld.wolfram.com/Set.html and https://en.wikipedia.org/wiki/Multiplicity_(mathematics) , both of which mention multisets.



                Another term that is used in the context of eigenvalues is "spectrum": the multiplicity of the eigenvalues is important, but there is no canonical order (other than the normal order of the real numbers, but that doesn't apply if they are complex). When you diagonalize or take the Jordan canonical form of a matrix, it matters how many times each eigenvalue appears, but putting the eigenvalues in a different order results in the same matrix, up to similarity.






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                  4 Answers
                  4






                  active

                  oldest

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                  4 Answers
                  4






                  active

                  oldest

                  votes









                  active

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                  votes






                  active

                  oldest

                  votes









                  35












                  $begingroup$

                  If you're looking for something like a set which may have repeated elements, standard terms are multiset or bag. See multiset on wikipedia.






                  share|cite|improve this answer









                  $endgroup$


















                    35












                    $begingroup$

                    If you're looking for something like a set which may have repeated elements, standard terms are multiset or bag. See multiset on wikipedia.






                    share|cite|improve this answer









                    $endgroup$
















                      35












                      35








                      35





                      $begingroup$

                      If you're looking for something like a set which may have repeated elements, standard terms are multiset or bag. See multiset on wikipedia.






                      share|cite|improve this answer









                      $endgroup$



                      If you're looking for something like a set which may have repeated elements, standard terms are multiset or bag. See multiset on wikipedia.







                      share|cite|improve this answer












                      share|cite|improve this answer



                      share|cite|improve this answer










                      answered Mar 25 at 11:24









                      Especially LimeEspecially Lime

                      22.8k23059




                      22.8k23059























                          7












                          $begingroup$

                          The common term is multiset. For a formal definition, you can for instance define the set of multisets of size $n$ of a given set $A$ as $A^n/mathfrak{S}_n$ where $mathfrak{S}_n$ acts by permutation of the factors; or if you don't want to be bothered by size you can define it as a map $f: Ato mathbb{N}$ where $f(a)$ is supposed to represent the number of times $a$ appears in the multiset.



                          These are two interesting models for different situations, and there are probably more.






                          share|cite|improve this answer









                          $endgroup$


















                            7












                            $begingroup$

                            The common term is multiset. For a formal definition, you can for instance define the set of multisets of size $n$ of a given set $A$ as $A^n/mathfrak{S}_n$ where $mathfrak{S}_n$ acts by permutation of the factors; or if you don't want to be bothered by size you can define it as a map $f: Ato mathbb{N}$ where $f(a)$ is supposed to represent the number of times $a$ appears in the multiset.



                            These are two interesting models for different situations, and there are probably more.






                            share|cite|improve this answer









                            $endgroup$
















                              7












                              7








                              7





                              $begingroup$

                              The common term is multiset. For a formal definition, you can for instance define the set of multisets of size $n$ of a given set $A$ as $A^n/mathfrak{S}_n$ where $mathfrak{S}_n$ acts by permutation of the factors; or if you don't want to be bothered by size you can define it as a map $f: Ato mathbb{N}$ where $f(a)$ is supposed to represent the number of times $a$ appears in the multiset.



                              These are two interesting models for different situations, and there are probably more.






                              share|cite|improve this answer









                              $endgroup$



                              The common term is multiset. For a formal definition, you can for instance define the set of multisets of size $n$ of a given set $A$ as $A^n/mathfrak{S}_n$ where $mathfrak{S}_n$ acts by permutation of the factors; or if you don't want to be bothered by size you can define it as a map $f: Ato mathbb{N}$ where $f(a)$ is supposed to represent the number of times $a$ appears in the multiset.



                              These are two interesting models for different situations, and there are probably more.







                              share|cite|improve this answer












                              share|cite|improve this answer



                              share|cite|improve this answer










                              answered Mar 25 at 11:27









                              MaxMax

                              15.9k11144




                              15.9k11144























                                  4












                                  $begingroup$

                                  In this context you can identify what you call a $mathbf{ set^*}$ with a function that has a finite domain and has $mathbb N={1,2,3cdots}$ as codomain.



                                  $A$ and $B$ in your question can both be identified with function: $${langle3,2rangle,langle4,2rangle,langle8,1rangle,langle11,1rangle}$$Domain of the function in this case is the set ${3,4,8,11}$.






                                  share|cite|improve this answer









                                  $endgroup$


















                                    4












                                    $begingroup$

                                    In this context you can identify what you call a $mathbf{ set^*}$ with a function that has a finite domain and has $mathbb N={1,2,3cdots}$ as codomain.



                                    $A$ and $B$ in your question can both be identified with function: $${langle3,2rangle,langle4,2rangle,langle8,1rangle,langle11,1rangle}$$Domain of the function in this case is the set ${3,4,8,11}$.






                                    share|cite|improve this answer









                                    $endgroup$
















                                      4












                                      4








                                      4





                                      $begingroup$

                                      In this context you can identify what you call a $mathbf{ set^*}$ with a function that has a finite domain and has $mathbb N={1,2,3cdots}$ as codomain.



                                      $A$ and $B$ in your question can both be identified with function: $${langle3,2rangle,langle4,2rangle,langle8,1rangle,langle11,1rangle}$$Domain of the function in this case is the set ${3,4,8,11}$.






                                      share|cite|improve this answer









                                      $endgroup$



                                      In this context you can identify what you call a $mathbf{ set^*}$ with a function that has a finite domain and has $mathbb N={1,2,3cdots}$ as codomain.



                                      $A$ and $B$ in your question can both be identified with function: $${langle3,2rangle,langle4,2rangle,langle8,1rangle,langle11,1rangle}$$Domain of the function in this case is the set ${3,4,8,11}$.







                                      share|cite|improve this answer












                                      share|cite|improve this answer



                                      share|cite|improve this answer










                                      answered Mar 25 at 11:33









                                      drhabdrhab

                                      104k545136




                                      104k545136























                                          1












                                          $begingroup$

                                          If two objects can be distinguished by the number of times an element appears in them, that is called "multiplicity". So the more mathy version of "finite collection of unordered objects that are not necessarily distinct" would be "unordered finite collection with multiplicity" or "finite collection with multiplicity but not order".



                                          The single-word term for unordered collections with multiplicity is "multi-set", but I don't think there's any single-word term for finite multi-sets. Googling "math collection multiplicity no order" returns http://mathworld.wolfram.com/Set.html and https://en.wikipedia.org/wiki/Multiplicity_(mathematics) , both of which mention multisets.



                                          Another term that is used in the context of eigenvalues is "spectrum": the multiplicity of the eigenvalues is important, but there is no canonical order (other than the normal order of the real numbers, but that doesn't apply if they are complex). When you diagonalize or take the Jordan canonical form of a matrix, it matters how many times each eigenvalue appears, but putting the eigenvalues in a different order results in the same matrix, up to similarity.






                                          share|cite|improve this answer









                                          $endgroup$


















                                            1












                                            $begingroup$

                                            If two objects can be distinguished by the number of times an element appears in them, that is called "multiplicity". So the more mathy version of "finite collection of unordered objects that are not necessarily distinct" would be "unordered finite collection with multiplicity" or "finite collection with multiplicity but not order".



                                            The single-word term for unordered collections with multiplicity is "multi-set", but I don't think there's any single-word term for finite multi-sets. Googling "math collection multiplicity no order" returns http://mathworld.wolfram.com/Set.html and https://en.wikipedia.org/wiki/Multiplicity_(mathematics) , both of which mention multisets.



                                            Another term that is used in the context of eigenvalues is "spectrum": the multiplicity of the eigenvalues is important, but there is no canonical order (other than the normal order of the real numbers, but that doesn't apply if they are complex). When you diagonalize or take the Jordan canonical form of a matrix, it matters how many times each eigenvalue appears, but putting the eigenvalues in a different order results in the same matrix, up to similarity.






                                            share|cite|improve this answer









                                            $endgroup$
















                                              1












                                              1








                                              1





                                              $begingroup$

                                              If two objects can be distinguished by the number of times an element appears in them, that is called "multiplicity". So the more mathy version of "finite collection of unordered objects that are not necessarily distinct" would be "unordered finite collection with multiplicity" or "finite collection with multiplicity but not order".



                                              The single-word term for unordered collections with multiplicity is "multi-set", but I don't think there's any single-word term for finite multi-sets. Googling "math collection multiplicity no order" returns http://mathworld.wolfram.com/Set.html and https://en.wikipedia.org/wiki/Multiplicity_(mathematics) , both of which mention multisets.



                                              Another term that is used in the context of eigenvalues is "spectrum": the multiplicity of the eigenvalues is important, but there is no canonical order (other than the normal order of the real numbers, but that doesn't apply if they are complex). When you diagonalize or take the Jordan canonical form of a matrix, it matters how many times each eigenvalue appears, but putting the eigenvalues in a different order results in the same matrix, up to similarity.






                                              share|cite|improve this answer









                                              $endgroup$



                                              If two objects can be distinguished by the number of times an element appears in them, that is called "multiplicity". So the more mathy version of "finite collection of unordered objects that are not necessarily distinct" would be "unordered finite collection with multiplicity" or "finite collection with multiplicity but not order".



                                              The single-word term for unordered collections with multiplicity is "multi-set", but I don't think there's any single-word term for finite multi-sets. Googling "math collection multiplicity no order" returns http://mathworld.wolfram.com/Set.html and https://en.wikipedia.org/wiki/Multiplicity_(mathematics) , both of which mention multisets.



                                              Another term that is used in the context of eigenvalues is "spectrum": the multiplicity of the eigenvalues is important, but there is no canonical order (other than the normal order of the real numbers, but that doesn't apply if they are complex). When you diagonalize or take the Jordan canonical form of a matrix, it matters how many times each eigenvalue appears, but putting the eigenvalues in a different order results in the same matrix, up to similarity.







                                              share|cite|improve this answer












                                              share|cite|improve this answer



                                              share|cite|improve this answer










                                              answered Mar 25 at 15:50









                                              AcccumulationAcccumulation

                                              7,2152619




                                              7,2152619






























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