In order to present a concept in an article, I need an operation in which the order of elements does not matter but repetitions is allowed.
For example, if a have some vectors [1 2 3], [2 3 1], [1 2 3], how can denote that I'm building a multiset V = {[1 2 3], [1 2 3], [2 3 1]} (in which the order does not matter)?
If I use union: $$ [1\ 2\ 3] \cup [2\ 3\ 1] \cup [1\ 2\ 3] = \{[1\ 2\ 3], [2\ 3\ 1]\} $$
Correct? In this case I'm missing one repetition of one element... what operation should I use?