The crossing number of K2,m□PnK2,m□Pn

Investigation of the crossing number of graphs is a classical but very difficult problem. The exact value of the crossing number is known only for a few specific families of graphs. In this paper we extend a recent result from Bokal on the crossing number of K1,m□PnK1,m□Pn, and prove that cr(K2,m□Pn)=2n⌊m2⌋⌊m−12⌋.