The degree distribution equation has the general form a + 2b + 3c + 4d = 2(n - 1 + r), where n is the number of skeletal atoms (usually carbon atoms), r is the number of rings (very liberally defined), and a, b, c, and d denote the numbers of skeletal atoms of degrees 1, 2, 3, and 4, respectively. For a given n and r there are normally numerous [a,b,c,d] solutions, all readily obtainable by a computer program. Each solution represents a valid degree distribution. All isomers that conform to a certain degree distribution can be considered to belong to the same domain. A maximal degree distribution is defined as a degree distribution [a,b,c,d] in which at least one term is maximal for the given n and r. Maximal values follow a predictable pattern for an infinite range of n for the chosen r and are easily calculated for any desired case.
