On integral graphs which belong to the class $overline {alpha K_{a,a} cup beta {rm K}_{b,b} } $

摘要

LetG be a simple graph and letG denote its complement. We say thatG is integral if its spectrum consists of integral values. In this work we establish a characterization of integral graphs which belong to the class $overline {alpha K_{a,a} cup beta {rm K}_{b,b} } $ wheremG denotes them-fold union of the graphG.