Keywords: Not upward planar.svg upward planar drawing In a planar DAG with a single source and sink an upward drawing can exist only if the source and sink are both on the outer face of the drawing but that is impossible for this graph 2013-08-03 20 59 27 own David Eppstein cc-zero Directed planar graphs Files by User David Eppstein from en Uploaded with UploadWizard |