Sets
From NARS2000


L is a scalar or oneelement vector.  
R is a scalar or oneelement vector.  
Z is the vector result equivalent to (L~R),R~L. 


L is a scalar or oneelement vector.  
R is a scalar or oneelement vector.  
Z is the Boolean scalar result equivalent to ∧/L∊R as well as R⊇L. 


L is a scalar or oneelement vector.  
R is a scalar or oneelement vector.  
Z is the Boolean scalar result equivalent to ∧/R∊L as well as R⊆L. 
These functions behave differently when invoked via the Multiset Operator which takes into account multiplicities.
For example,
'miasma'§'sis'
mama
'miasma'§⍦'sis' ⍝ Using the Multiset form
mamas
'immiss'⊆'mississippi'
1
'immiss'⊆⍦'mississippi' ⍝ Using the Multiset form
0 ⍝ because the # m's doesn't match