The irregularity sum e ( g ) of the graph g is the minimum sum of vertex labels among all irregular networks having g as an underlying graph . a garph g for wich ( g ) = n + ( n2 ) is called consecutive 图g的非正则和是在所有以g为基础图的非正则网络中,各顶点标号的和为最小的值,记为( g ) 。