Graphical sequences are determined by the majorization order

Abstract

This paper studies the relation between the Lorenz majorization order and the realizability of degree sequences X of a network in the sense of being graphical or connected graphical c-graphical or not. We prove the main result that, if X is dominated (in the Lorenz majorization sense) by Y and Y is c- graphical, then X is also (c-) graphical. From this, a classical result of Hakimi on trees follows but also a new generalization of it to general connected networks. Moreover, a characterization of c-graphical sequences in terms of the Lorenz majorization order is given.