combination definition

1. <mathematics> A set containing a certain number of objects selected from another set.

The number of combinations of r objects chosen from a set of n is

n C r = n! / ((n-r)! r!)

where "n C r" is normally with n and r as subscripts or as n above r in parentheses.

See also: permutation.

2. <reduction> In the theory of combinators, a combination denotes an expression in which function application is the only operation.

The result or product of combining, a series of events or result occurring in an ordered sequence, the act or process of combining, the act or process of uniting to form a chemical compound: the chemical compound so formed.

<zoology> The name of a species or subspecies consisting of the name of the genus followed by the specific or specific plus subspecific names.

(09 Jan )