The old DOS version is no longer distributed. Missing values are allowed and should be indicated by a negative integer, or a question mark. Multi state characters may be expressed in binary form. Each block of binary states represents one multi state character, thus avoiding the errors that are introduced when each state of a multi state character is treated as a separate nominal variable. Polymorphism can be indicated, but only in the binary expression of multi-state characters.
Components are compatible when they either include, exclude, or replicate each other.
Components of a cladogram can be seen as nodes of a graph, connected by lines depicting the compatibility relation. Components can be defined in terms of character states in several ways. Components thus defined are seen as nodes in a graph, connected when they are compatible. Each clique corresponds to a cladogram. Note that component compatibility is, in general, not the same as character compatibility .