Suppose I am given the numbers from 1 to 9:
1 2 3 4 5 6 7 8 9
I filter out the prime numbers:
2 3 5 7 (A)
and I am left with:
1 4 6 8 9 (B)
What do you call (A) and (B) with respect to the filtering?
I am not sure if "filtered out" refers to the component which was removed, or the component which was retained.
Best Answer
Mathematicians use the term residue for anything left over, which fits nicely with the concept of filtering. I would call (B) the residue and (A) the filtrate in your example. The residue in this case, by the way, is the union of the positive composites and the unit 1.
Wikipedia
Oxford Dictionaries
Often also called the remainder, which is listed as a synonym for residue at Oxford dictionaries, but the more usual expression in Mathematics is to call it a residue.
Also, from Mathworld