A, b,c in the domain of all positive integers, in a proof to the theorem a3+b3+c3≥a2b+b2c+c2aa3+b3+c3≥a2b+b2 c+c2a, we may assume without loss of generality that:
a. a≥b, a≥ca≥b, a≥c
b. a≥b, b≥ca≥b, b≥c
c. a≥c, c≥ba≥c, c≥b
d. a≥c, b≥c