“…The node-to-circle expansion operation preserves more properties, such as 3connectivity and the genus, and it may simplify graphs. For example, complete bipartite graphs K 4,n are fan-crossing but are not k-planar for k = 0, 1, 2, 3, 4 and n = 3, 5, 7, 10, 19, respectively, as shown by Angelini et al [9]. Also K 4,7 is not fan-crossing free.…”