An atom that has been stripped of its valence electrons, or a positively charged nucleus lacking the outermost orbital electrons.

1. The inner portion of a seed.

2. A whole grain or seed of a cereal plant, such as corn or barley.

1. A computer program that must be modified before it can be used on a particular computer.

2. The programs that form the most essential part of a computer's operating system.

1. For any mapping f from a group A to a group B, the kernel of f, denoted ker f, is the set of all elements a of A such that f (a ) equals the identity element of B.

2. For a homomorphism h from a group G to a group H, this consists of all elements of G which h sends to the identity element of H.

3. For Fredholm and Volterra integral equations, this is the function K(x,t ).

4. For an integral transform, the function K(x, t ) in the transformation which sends the function f (x ) to the function ∫ K(x,t )f (t )dt = F (x ).

5. See <<null space>>