Difference between three quantities
  The notion of difference between two quantities plays a basic role in mathematics, consequently in all branches of human activity where the mathematics is applied. However the long stand question is: what is the difference between three (or more) quantities?   The binary operation [a,b]=(a-b) possesses the following principal feature: with respect to the third quantity (c) this operation is decomposed into a sum of the same operations between (a) and (c), and (c)and (b), i.e., [a,b]=[a,c]+[c,b].   Denote by [a,b,c] difference between three quantities (a,b,c). With respect to additional quantity (d) this definition of the difference has to possess with the following property [a,b,c]=[d,b,c]+[a,d,c]+[a,b,d].   We prove that this property of difference between three (or n>2) quantities is satisfied by one of the features of Vandermonde determinant. 
Robert M. Yamaleev
math.HO