2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/230338The Yao graph for k=4, Y4, is naturally partitioned into four subgraphs, one per quadrant. We show that the subgraphs for one quadrant differ from the subgraphs for two adjacent quadrants in three properties: planarity, connectedness, and whether the directed graphs are spanners.7 pages, 6 figuresComputational GeometryDiscrete MathematicsF.2.2text