jmundsack
asked on
Mathematical Terminology
Thinking along the lines of permutations, I wonder what the precise terminology is to describe the following (and I know permutations is NOT the correct term):
I have a set of numbers, say:
{26, 74, 92}
From this I want to create sets that include 1 or more values from the original set, any any order, but never repeating the same member of the set. To express it in binary, it would look like this:
100
010
110
001
101
011
111
Which equates to these sets:
{26}
{74}
{26, 74}
{92}
{26, 92}
{74, 92}
{26, 74, 92}
Does that make sense? What I've done is solved a problem where I have a value, say x, and I want to find out which subsets of the original value set, sum up to x. The program works, but I know I'm using the wrong terminology when I call it "permutations," which by definition involves all the members of the original set.
In looking on the web, I found something that suggests it should be called "k-combinations", but this is a little above my head:
(From Wikipedia)
In combinatorial mathematics, a combination is an un-ordered collection of unique elements. Given S, the set of all possible unique elements, a combination is a subset of the elements of S. The order of the elements in a combination is not important (two lists with the same elements in different orders are considered to be the same combination). Also, the elements cannot be repeated in a combination (every element appears uniquely once). A k-combination (or k-subset) is a subset with k elements. The number of k-combinations (each of size k) from a set S with n elements (size n) is the binomial coefficient
Does anyone know for sure what I would call this operation?
I have a set of numbers, say:
{26, 74, 92}
From this I want to create sets that include 1 or more values from the original set, any any order, but never repeating the same member of the set. To express it in binary, it would look like this:
100
010
110
001
101
011
111
Which equates to these sets:
{26}
{74}
{26, 74}
{92}
{26, 92}
{74, 92}
{26, 74, 92}
Does that make sense? What I've done is solved a problem where I have a value, say x, and I want to find out which subsets of the original value set, sum up to x. The program works, but I know I'm using the wrong terminology when I call it "permutations," which by definition involves all the members of the original set.
In looking on the web, I found something that suggests it should be called "k-combinations", but this is a little above my head:
(From Wikipedia)
In combinatorial mathematics, a combination is an un-ordered collection of unique elements. Given S, the set of all possible unique elements, a combination is a subset of the elements of S. The order of the elements in a combination is not important (two lists with the same elements in different orders are considered to be the same combination). Also, the elements cannot be repeated in a combination (every element appears uniquely once). A k-combination (or k-subset) is a subset with k elements. The number of k-combinations (each of size k) from a set S with n elements (size n) is the binomial coefficient
Does anyone know for sure what I would call this operation?
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