hi,
according to http://topdefinitions.com/multisets-and-their-operations/
the difference between multisets is defined as:
The difference of two multisets A and B, is a multiset such that the
multiplicity of an element is equal to the multiplicity of an element
in A minus multiplicity of an element in B, if the difference is +ve,
and it is equal to 0 if the difference is 0 and –ve. It is denoted by
A-B.
e.g.
A={l,l,m,m,m,n,n}
B={l,m,m,n,n,n}
A-B={l,m}
however in pike:
> multiset A =(< "l","l","m","m","m","n","n">);
> multiset B =(< "l","m","m","n","n","n">);
> A-B;
Result: (< >)
greetings, martin.
