Introduction: The Shift Algorithm 3 [de Fraysseix, Pach, and Pollack, 1990] [Chrobak and Payne, 1995] Idea: v 4 v 6 • Triangulate given plane graph. • Compute a canonical ordering of v 3 v 5 the vertices v 1 , v 2 , . . . , v n . v 2 v 1 • Draw the graph: Resulting grid size: – Start with triangle v 1 , v 2 , v 3 . (2 n − 4) × ( n − 2) – For v k : v 6 Shift first & last neighbor of v k . – Add v k to the outer face. ⇒ all slopes on outer face ± 1 v 5 v 4 v 3 (except for v 1 v 2 ) v 1 v 2
Introduction: The Shift Algorithm 3 [de Fraysseix, Pach, and Pollack, 1990] [Chrobak and Payne, 1995] Idea: v 4 v 6 • Triangulate given plane graph. • Compute a canonical ordering of v 3 v 5 the vertices v 1 , v 2 , . . . , v n . v 2 v 1 • Draw the graph: Resulting grid size: – Start with triangle v 1 , v 2 , v 3 . (2 n − 4) × ( n − 2) – For v k : v 6 Shift first & last neighbor of v k . – Add v k to the outer face. ⇒ all slopes on outer face ± 1 v 5 v 4 v 3 (except for v 1 v 2 ) v 1 v 2
Introduction: Related Work 4 1-planar = { graph G | G has a NIC-planar drawing } NIC-planar contained in (even for fixed embedding) IC-planar E ? contained in (unknown for fixed embedding) planar incomparable
Introduction: Related Work 4 RAC 2 RAC 1 1-planar RAC 0 NIC-planar contained in (even for fixed embedding) IC-planar E ? contained in (unknown for fixed embedding) planar incomparable
Introduction: Related Work 4 RAC poly 3 RAC 2 RAC poly 2 RAC 1 RAC poly 1 1-planar RAC 0 RAC poly 0 NIC-planar contained in (even for fixed embedding) IC-planar E ? contained in (unknown for fixed embedding) planar incomparable
Introduction: Related Work 4 RAC poly [de Fraysseix, Pach, Pollack, 3 1990] RAC 2 [Schnyder, 1990] RAC poly 2 RAC 1 RAC poly 1 1-planar RAC 0 RAC poly 0 NIC-planar contained in (even for fixed embedding) IC-planar E ? contained in (unknown for fixed embedding) planar incomparable
Introduction: Related Work 4 RAC poly RAC poly [Didimo, Eades, Liotta, = all graphs = all graphs E ? E ? 3 3 2009] RAC 2 RAC poly 2 RAC 1 RAC poly 1 1-planar RAC 0 RAC poly 0 NIC-planar contained in (even for fixed embedding) IC-planar E ? contained in (unknown for fixed embedding) planar incomparable
Introduction: Related Work 4 RAC poly [Didimo, Eades, Liotta, = all graphs E ? 3 2009] RAC 2 [Eades, Liotta, 2011] RAC poly 2 RAC 1 RAC poly 1 1-planar RAC 0 RAC poly 0 NIC-planar contained in (even for fixed embedding) IC-planar E ? contained in (unknown for fixed embedding) planar incomparable
Introduction: Related Work 4 RAC poly [Brandenburg, Didimo, = all graphs E ? 3 Evans, Kindermann, Liotta, RAC 2 Montecchiani, 2015] RAC poly 2 RAC 1 RAC poly 1 1-planar RAC 0 RAC poly 0 E ? E ? NIC-planar contained in (even for fixed embedding) IC-planar E ? contained in (unknown for fixed embedding) planar incomparable
Introduction: Related Work 4 RAC poly [Liotta, Montecchiani, 2015] = all graphs E ? 3 RAC 2 RAC poly 2 RAC 1 RAC poly 1 1-planar RAC 0 RAC poly 0 E ? NIC-planar contained in (even for fixed embedding) IC-planar E ? contained in (unknown for fixed embedding) planar incomparable
Introduction: Related Work 4 RAC poly [Didimo, Liotta, Mehrabi, = all graphs E ? 3 Montecchiani, 2016] RAC 2 RAC poly 2 RAC 1 E ? E ? RAC poly 1 1-planar RAC 0 RAC poly 0 E ? NIC-planar contained in (even for fixed embedding) IC-planar E ? contained in (unknown for fixed embedding) planar incomparable
Introduction: Related Work 4 RAC poly [Bachmaier, Brandenburg, = all graphs E ? 3 Hanauer, Neuwirth, RAC 2 Reislhuber, 2017] RAC poly 2 RAC 1 E ? RAC poly 1 1-planar RAC 0 RAC poly 0 E ? NIC-planar contained in (even for fixed embedding) IC-planar E ? contained in (unknown for fixed embedding) planar incomparable
Introduction: Related Work 4 RAC poly = all graphs E ? 3 RAC 2 RAC poly Our results 2 RAC 1 E ? RAC poly 1 1-planar RAC 0 RAC poly 0 E ? NIC-planar contained in (even for fixed embedding) IC-planar E ? contained in (unknown for fixed embedding) planar incomparable
Introduction: Related Work 4 RAC poly = all graphs E ? 3 RAC 2 RAC poly Our results 2 RAC 1 E ? RAC poly 1 1-planar RAC 0 RAC poly w/o B-configuration 0 E ? NIC-planar contained in (even for fixed embedding) IC-planar E ? contained in (unknown for fixed embedding) planar incomparable
Introduction: Related Work 4 RAC poly = all graphs E ? 3 RAC 2 RAC poly 2 RAC 1 E ? Our first main result: RAC poly 1 1-planar RAC 0 NIC-plane graphs RAC poly ⊆ RAC poly w/o B-configuration 0 1 E ? NIC-planar contained in (even for fixed embedding) IC-planar E ? contained in (unknown for fixed embedding) planar incomparable
Introduction: Related Work 4 RAC poly Our second main result: = all graphs E ? 3 RAC 2 1-plane graphs RAC poly ⊆ RAC poly 2 2 RAC 1 E ? Our first main result: RAC poly 1 1-planar RAC 0 NIC-plane graphs RAC poly ⊆ RAC poly w/o B-configuration 0 1 E ? NIC-planar contained in (even for fixed embedding) IC-planar E ? contained in (unknown for fixed embedding) planar incomparable
Result 1: NIC-Plane Graphs ⊆ RAC poly 5 1 RAC poly = all graphs E ? 3 RAC 2 RAC poly 2 RAC 1 RAC poly 1 1-planar RAC 0 RAC poly w/o B-configuration 0 NIC-planar IC-planar planar
Result 1: NIC-Plane Graphs ⊆ RAC poly 6 1 • Input: a NIC-plane graph
Result 1: NIC-Plane Graphs ⊆ RAC poly 6 1 • Input: a NIC-plane graph Approach that nearly works:
Result 1: NIC-Plane Graphs ⊆ RAC poly 6 1 • Input: a NIC-plane graph Approach that nearly works:
Result 1: NIC-Plane Graphs ⊆ RAC poly 6 1 • Input: a NIC-plane graph Approach that nearly works: • Enclose each crossing by a so called empty kite :
Result 1: NIC-Plane Graphs ⊆ RAC poly 6 1 • Input: a NIC-plane graph Approach that nearly works: • Enclose each crossing by a so called empty kite : v dummy
Result 1: NIC-Plane Graphs ⊆ RAC poly 6 1 • Input: a NIC-plane graph Approach that nearly works: • Enclose each crossing by a so called empty kite : • Replace each pair of crossing edges by a single edge v dummy
Result 1: NIC-Plane Graphs ⊆ RAC poly 6 1 • Input: a NIC-plane graph Approach that nearly works: • Enclose each crossing by a so called empty kite : • Replace each pair of crossing edges by a single edge v dummy
Result 1: NIC-Plane Graphs ⊆ RAC poly 6 1 • Input: a NIC-plane graph Approach that nearly works: • Enclose each crossing by a so called empty kite : • Replace each pair of crossing edges by a single edge • Draw the obtained plane graph with the Shift Algorithm v dummy
Result 1: NIC-Plane Graphs ⊆ RAC poly 6 1 • Input: a NIC-plane graph Approach that nearly works: • Enclose each crossing by a so called empty kite : • Replace each pair of crossing edges by a single edge • Draw the obtained plane graph with the Shift Algorithm v dummy
Result 1: NIC-Plane Graphs ⊆ RAC poly 6 1 • Input: a NIC-plane graph Approach that nearly works: • Enclose each crossing by a so called empty kite : • Replace each pair of crossing edges by a single edge • Draw the obtained plane graph with the Shift Algorithm • Manually reinsert the removed edges with 1 bend so that they cross in a right angle (crossings and bends on the grid) v dummy
Result 1: NIC-Plane Graphs ⊆ RAC poly 6 1 • Input: a NIC-plane graph Approach that nearly works: • Enclose each crossing by a so called empty kite : • Replace each pair of crossing edges by a single edge • Draw the obtained plane graph with the Shift Algorithm • Manually reinsert the removed edges with 1 bend so that they cross in a right angle (crossings and bends on the grid) v dummy
Result 1: NIC-Plane Graphs ⊆ RAC poly 6 1 • Input: a NIC-plane graph Approach that nearly works: • Enclose each crossing by a so called empty kite : • Replace each pair of crossing edges by a single edge • Draw the obtained plane graph with the Shift Algorithm • Manually reinsert the removed edges with 1 bend so that they cross in a right angle (crossings and bends on the grid) v dummy
Result 1: NIC-Plane Graphs ⊆ RAC poly 6 1 • Input: a NIC-plane graph Approach that nearly works: • Enclose each crossing by a so called empty kite : • Replace each pair of crossing edges by a single edge • Draw the obtained plane graph with the Shift Algorithm • Manually reinsert the removed edges with 1 bend so that they cross in a right angle (crossings and bends on the grid) grid point on the Thales’ circle v dummy
Result 1: NIC-Plane Graphs ⊆ RAC poly 6 1 • Input: a NIC-plane graph Approach that nearly works: • Enclose each crossing by a so called empty kite : • Replace each pair of crossing edges by a single edge • Draw the obtained plane graph with the Shift Algorithm • Manually reinsert the removed edges with 1 bend so that they cross in a right angle (crossings and bends on the grid) grid point on the Thales’ circle v dummy
Result 1: NIC-Plane Graphs ⊆ RAC poly 6 1 • Input: a NIC-plane graph Approach that nearly works: • Enclose each crossing by a so called empty kite : • Replace each pair of crossing edges by a single edge • Draw the obtained plane graph with the Shift Algorithm • Manually reinsert the removed edges with 1 bend so that they cross in a right angle (crossings and bends on the grid) grid points for the bends v dummy
Result 1: NIC-Plane Graphs ⊆ RAC poly 6 1 • Input: a NIC-plane graph Approach that nearly works: • Enclose each crossing by a so called empty kite : • Replace each pair of crossing edges by a single edge • Draw the obtained plane graph with the Shift Algorithm • Manually reinsert the removed edges with 1 bend so that they cross in a right angle (crossings and bends on the grid) � v dummy
Result 1: NIC-Plane Graphs ⊆ RAC poly 6 1 • Input: a NIC-plane graph Approach that nearly works: • Enclose each crossing by a so called empty kite : • Replace each pair of crossing edges by a single edge • Draw the obtained plane graph with the Shift Algorithm • Manually reinsert the removed edges with 1 bend so that they cross in a right angle (crossings and bends on the grid) � v dummy
Result 1: NIC-Plane Graphs ⊆ RAC poly 6 1 • Input: a NIC-plane graph Approach that nearly works: • Enclose each crossing by a so called empty kite : • Replace each pair of crossing edges by a single edge • Draw the obtained plane graph with the Shift Algorithm • Manually reinsert the removed edges with 1 bend so that they cross in a right angle (crossings and bends on the grid) � v dummy
Result 1: NIC-Plane Graphs ⊆ RAC poly 6 1 • Input: a NIC-plane graph Approach that nearly works: • Enclose each crossing by a so called empty kite : • Replace each pair of crossing edges by a single edge • Draw the obtained plane graph with the Shift Algorithm • Manually reinsert the removed edges with 1 bend so that they cross in a right angle (crossings and bends on the grid) � very slim v dummy
Result 1: NIC-Plane Graphs ⊆ RAC poly 6 1 • Input: a NIC-plane graph Approach that nearly works: • Enclose each crossing by a so called empty kite : • Replace each pair of crossing edges by a single edge • Draw the obtained plane graph with the Shift Algorithm • Manually reinsert the removed edges with 1 bend so that they cross in a right angle (crossings and bends on the grid) � v dummy
Result 1: NIC-Plane Graphs ⊆ RAC poly 6 1 • Input: a NIC-plane graph Approach that nearly works: • Enclose each crossing by a so called empty kite : • Replace each pair of crossing edges by a single edge • Draw the obtained plane graph with the Shift Algorithm • Manually reinsert the removed edges with 1 bend so that they cross in a right angle (crossings and bends on the grid) � v dummy
Result 1: NIC-Plane Graphs ⊆ RAC poly 6 1 • Input: a NIC-plane graph Approach that nearly works: • Enclose each crossing by a so called empty kite : • Replace each pair of crossing edges by a single edge • Draw the obtained plane graph with the Shift Algorithm • Manually reinsert the removed edges with 1 bend so that they cross in a right angle (crossings and bends on the grid) � v dummy
Result 1: NIC-Plane Graphs ⊆ RAC poly 6 1 • Input: a NIC-plane graph Approach that nearly works: • Enclose each crossing by a so called empty kite : • Replace each pair of crossing edges by a single edge • Draw the obtained plane graph with the Shift Algorithm • Manually reinsert the removed edges with 1 bend so that they cross in a right angle (crossings and bends on the grid) � v dummy
Result 1: NIC-Plane Graphs ⊆ RAC poly 6 1 • Input: a NIC-plane graph Approach that nearly works: • Enclose each crossing by a so called empty kite : • Replace each pair of crossing edges by a single edge • Draw the obtained plane graph with the Shift Algorithm • Manually reinsert the removed edges with 1 bend so that they cross in a right angle (crossings and bends on the grid) � v dummy bad configu- ration!
Result 1: NIC-Plane Graphs ⊆ RAC poly 7 1 bad configu- ration!
Result 1: NIC-Plane Graphs ⊆ RAC poly 7 1 bad Solution: configu- ration! • Make the first vertex in the qudrangle (regarding the canonical ordering) adjacent to the other three vertices.
Result 1: NIC-Plane Graphs ⊆ RAC poly 7 1 bad Solution: configu- ration! • Make the first vertex in the qudrangle (regarding the canonical ordering) adjacent to the other three vertices. • Use the algorithm by Harel and Sardas (Shift Algorithm for biconnected graphs).
Result 1: NIC-Plane Graphs ⊆ RAC poly 7 1 bad Solution: configu- ration! • Make the first vertex in the qudrangle (regarding the canonical ordering) adjacent to the other three vertices. • Use the algorithm by Harel and Sardas (Shift Algorithm for biconnected graphs). It builds a canonical ordering bottom-up instead of top-down.
Result 1: NIC-Plane Graphs ⊆ RAC poly 7 1 bad Solution: configu- ration! • Make the first vertex in the qudrangle (regarding the canonical ordering) adjacent to the other three vertices. • Use the algorithm by Harel and Sardas (Shift Algorithm for biconnected graphs). It builds a canonical ordering bottom-up start with instead of top-down. an empty quadrangle
Result 1: NIC-Plane Graphs ⊆ RAC poly 7 1 bad Solution: configu- ration! • Make the first vertex in the qudrangle (regarding the canonical ordering) adjacent to the other three vertices. • Use the algorithm by Harel and Sardas (Shift Algorithm for biconnected graphs). v 42 It builds a canonical ordering bottom-up instead of top-down.
Result 1: NIC-Plane Graphs ⊆ RAC poly 7 1 bad Solution: configu- ration! • Make the first vertex in the qudrangle (regarding the canonical ordering) adjacent to the other three vertices. • Use the algorithm by Harel and Sardas (Shift Algorithm for biconnected graphs). v 42 It builds a canonical ordering bottom-up instead of top-down. Insert the diagonal
Result 1: NIC-Plane Graphs ⊆ RAC poly 7 1 bad Solution: configu- ration! • Make the first vertex in the qudrangle (regarding the canonical ordering) adjacent to the other three vertices. • Use the algorithm by Harel and Sardas (Shift Algorithm for biconnected graphs). v 42 It builds a canonical ordering bottom-up instead of top-down. Insert the diagonal
Result 1: NIC-Plane Graphs ⊆ RAC poly 7 1 bad Solution: configu- ration! • Make the first vertex in the qudrangle (regarding the canonical ordering) adjacent to the other three vertices. v 55 • Use the algorithm by Harel and Sardas (Shift Algorithm for biconnected graphs). v 42 It builds a canonical ordering bottom-up instead of top-down.
Result 1: NIC-Plane Graphs ⊆ RAC poly 7 1 bad Solution: configu- ration! • Make the first vertex in the qudrangle (regarding the canonical ordering) adjacent to the other three vertices. v 55 v 61 • Use the algorithm by Harel and Sardas (Shift Algorithm for biconnected graphs). v 42 It builds a canonical ordering bottom-up instead of top-down.
Result 1: NIC-Plane Graphs ⊆ RAC poly 7 1 bad Solution: configu- ration! • Make the first vertex in the qudrangle (regarding the canonical ordering) adjacent to the other three vertices. v 55 v 61 • Use the algorithm by Harel and Sardas (Shift Algorithm for biconnected graphs). v 42 It builds a canonical ordering bottom-up instead of top-down. v 94
Result 1: NIC-Plane Graphs ⊆ RAC poly 7 1 bad Solution: configu- ration! • Make the first vertex in the qudrangle (regarding the canonical ordering) adjacent to the other three vertices. v 55 v 61 • Use the algorithm by Harel and Sardas (Shift Algorithm for biconnected graphs). v 42 It builds a canonical ordering bottom-up instead of top-down. v 94 • Now only three “good” cases can appear:
Result 1: NIC-Plane Graphs ⊆ RAC poly 7 1 bad Solution: configu- ration! • Make the first vertex in the qudrangle (regarding the canonical ordering) adjacent to the other three vertices. v 55 v 61 • Use the algorithm by Harel and Sardas (Shift Algorithm for biconnected graphs). v 42 It builds a canonical ordering bottom-up instead of top-down. v 94 • Now only three “good” cases can appear: Case 1
Result 1: NIC-Plane Graphs ⊆ RAC poly 7 1 bad Solution: configu- ration! • Make the first vertex in the qudrangle (regarding the canonical ordering) adjacent to the other three vertices. v 55 v 61 • Use the algorithm by Harel and Sardas (Shift Algorithm for biconnected graphs). v 42 It builds a canonical ordering bottom-up instead of top-down. v 94 • Now only three “good” cases can appear: Case 1
Result 1: NIC-Plane Graphs ⊆ RAC poly 7 1 bad Solution: configu- ration! • Make the first vertex in the qudrangle (regarding the canonical ordering) adjacent to the other three vertices. v 55 v 61 • Use the algorithm by Harel and Sardas (Shift Algorithm for biconnected graphs). v 42 It builds a canonical ordering bottom-up instead of top-down. v 94 • Now only three “good” cases can appear: Case 1
Result 1: NIC-Plane Graphs ⊆ RAC poly 7 1 bad Solution: configu- ration! • Make the first vertex in the qudrangle (regarding the canonical ordering) adjacent to the other three vertices. v 55 v 61 • Use the algorithm by Harel and Sardas (Shift Algorithm for biconnected graphs). v 42 It builds a canonical ordering bottom-up instead of top-down. v 94 • Now only three “good” cases can appear: Case 1 Case 2
Result 1: NIC-Plane Graphs ⊆ RAC poly 7 1 bad Solution: configu- ration! • Make the first vertex in the qudrangle (regarding the canonical ordering) adjacent to the other three vertices. v 55 v 61 • Use the algorithm by Harel and Sardas (Shift Algorithm for biconnected graphs). v 42 It builds a canonical ordering bottom-up instead of top-down. v 94 • Now only three “good” cases can appear: Case 1 Case 2
Result 1: NIC-Plane Graphs ⊆ RAC poly 7 1 bad Solution: configu- ration! • Make the first vertex in the qudrangle (regarding the canonical ordering) adjacent to the other three vertices. v 55 v 61 • Use the algorithm by Harel and Sardas (Shift Algorithm for biconnected graphs). v 42 It builds a canonical ordering bottom-up instead of top-down. v 94 • Now only three “good” cases can appear: Case 1 Case 2
Result 1: NIC-Plane Graphs ⊆ RAC poly 7 1 bad Solution: configu- ration! • Make the first vertex in the qudrangle (regarding the canonical ordering) adjacent to the other three vertices. v 55 v 61 • Use the algorithm by Harel and Sardas (Shift Algorithm for biconnected graphs). v 42 It builds a canonical ordering bottom-up instead of top-down. v 94 • Now only three “good” cases can appear: Case 1 Case 2 Case 3
Result 1: NIC-Plane Graphs ⊆ RAC poly 7 1 bad Solution: configu- ration! • Make the first vertex in the qudrangle (regarding the canonical ordering) adjacent to the other three vertices. v 55 v 61 • Use the algorithm by Harel and Sardas (Shift Algorithm for biconnected graphs). v 42 It builds a canonical ordering bottom-up instead of top-down. v 94 • Now only three “good” cases can appear: Case 1 Case 2 Case 3
Result 1: NIC-Plane Graphs ⊆ RAC poly 7 1 bad Solution: configu- ration! • Make the first vertex in the qudrangle (regarding the canonical ordering) adjacent to the other three vertices. v 55 v 61 • Use the algorithm by Harel and Sardas (Shift Algorithm for biconnected graphs). v 42 It builds a canonical ordering bottom-up instead of top-down. v 94 • Now only three “good” cases can appear: Case 1 Case 2 Case 3
Result 1: NIC-Plane Graphs ⊆ RAC poly 8 1 Full example:
Result 1: NIC-Plane Graphs ⊆ RAC poly 8 1 Full example:
Result 2: 1-Plane Graphs ⊆ RAC poly 9 2 RAC poly = all graphs E ? 3 RAC 2 RAC poly 2 RAC 1 RAC poly 1 1-planar RAC 0 RAC poly w/o B-configuration 0 NIC-planar IC-planar planar
Result 2: 1-Plane Graphs ⊆ RAC poly 10 2 • Input: a 1-plane graph
Result 2: 1-Plane Graphs ⊆ RAC poly 10 2 • Input: a 1-plane graph Preprocessing:
Result 2: 1-Plane Graphs ⊆ RAC poly 10 2 • Input: a 1-plane graph Preprocessing:
Result 2: 1-Plane Graphs ⊆ RAC poly 10 2 • Input: a 1-plane graph Preprocessing: • Enclose each crossing by a so called subdivided kite :
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