Systems take much more specification. To say that a set of variables comprises a system is to hypothesize that each variable in the set is a function of every variable in the set. It is circular unless one realizes that it is meant to be used in a self-correcting inquiry process. In practice, sets of variables are said to be more or less systemically related. Variables are sets whose elements are called values.
Dependency is a relationship among variables.
V2 Items in the chart are correlations. If we observe all the value-correlations of V1 x V2 then the correlation between V1 and V2 is zero. V2 is a display of all possible combinations of the values of V1 and V2. In other words, values of V2 specify the values of V1. A system is a set of variables that maintain functional relations through time, where the present state of a given variable is dependent on its own past state as well as the other variables.