axiomatization of dependence
As noted by van der Waerden, it is possible to define the notion of dependence axiomatically in such a way that one can deal with linear dependence, algebraic dependence, and other sorts of dependence via a general theory. In this general theoretical framework, one can prove results about bases, dimension, and the like.
Let be a set. The basic object of this theory is a relation between and the power set
of . This relation satisfies the following three axioms:
Axiom 1
If is a subset of and , then .
Axiom 2
If, for some set and some , it happens that but not , then .
Axiom 3
If, for some sets and some , it happens that and, for every , it is the case that , then .