additive set function

additive set function

[¦ad·əd·iv ¦set ‚fəŋk·shən]
(mathematics)
A set function with the properties that (1) the union of any two sets in the range of the function is also in this range and (2) the value of the function at a finite union of disjoint sets in the range of the set function is equal to the sum of the values at each set in the union. Also known as finitely additive set function.