Patrizio Angelini, Henry F¨
- rster, Michael Hoffmann, Michael Kaufmann,
Stephen Kobourov, Giuseppe Liotta, Maurizio Patrignani
The QuaSEFE Problem
27th International Symposium on Graph Drawing and Network Visualization 2019
The QuaSEFE Problem Patrizio Angelini, Henry F orster, Michael - - PowerPoint PPT Presentation
The QuaSEFE Problem Patrizio Angelini, Henry F orster, Michael Hoffmann, Michael Kaufmann, Stephen Kobourov, Giuseppe Liotta, Maurizio Patrignani 27 th International Symposium on Graph Drawing and Network Visualization 2019 The QuaSEFE
Patrizio Angelini, Henry F¨
Stephen Kobourov, Giuseppe Liotta, Maurizio Patrignani
27th International Symposium on Graph Drawing and Network Visualization 2019
Simultaneous (Graph) Embedding with Fixed Edges
Simultaneous (Graph) Embedding with Fixed Edges Input: Set of planar graphs with shared vertex set v1 v1 v2 v2 v3 v4 v4 v5 v5 v3
Simultaneous (Graph) Embedding with Fixed Edges Input: Set of planar graphs with shared vertex set Output: Planar drawings for all graphs such that v1 v1 v2 v2 v3 v4 v4 v5 v5 v1 v5 v4 v2 v3 v3
Simultaneous (Graph) Embedding with Fixed Edges Input: Set of planar graphs with shared vertex set Output: Planar drawings for all graphs such that vertices have the same position in all drawings (simultaneous drawings) v1 v1 v2 v2 v3 v4 v4 v5 v5 v1 v5 v4 v2 v3 v3
Simultaneous (Graph) Embedding with Fixed Edges Input: Set of planar graphs with shared vertex set Output: Planar drawings for all graphs such that vertices have the same position in all drawings (simultaneous drawings) edges have the same representation in all drawings (fixed edges) v1 v1 v2 v2 v3 v4 v4 v5 v5 v1 v5 v4 v2 v3 v3
Simultaneous (Graph) Embedding with Fixed Edges
Simultaneous (Graph) Embedding with Fixed Edges
Simultaneous (Graph) Embedding with Fixed Edges Quasiplanarity
Simultaneous (Graph) Embedding with Fixed Edges Quasiplanarity Quasiplanar Embedding: No triple of edges crosses pairwise
Simultaneous (Graph) Embedding with Fixed Edges Quasiplanarity Quasiplanar Embedding: No triple of edges crosses pairwise forbidden
Simultaneous (Graph) Embedding with Fixed Edges Quasiplanarity Quasiplanar Embedding: No triple of edges crosses pairwise forbidden allowed (no triple)
Simultaneous (Graph) Embedding with Fixed Edges Quasiplanarity Quasiplanar Embedding: No triple of edges crosses pairwise forbidden allowed (no triple) Thickness two drawings (i.e. two-edge colorable drawings) are quasiplanar
Simultaneous (Graph) Embedding with Fixed Edges Quasiplanarity
Simultaneous (Graph) Embedding with Fixed Edges Quasiplanarity QuaSEFE Problem:
Simultaneous (Graph) Embedding with Fixed Edges Quasiplanarity QuaSEFE Problem: Input: Set of quasiplanar graphs with shared vertex set
Simultaneous (Graph) Embedding with Fixed Edges Quasiplanarity QuaSEFE Problem: Input: Set of quasiplanar graphs with shared vertex set Output: Simultaneous quasiplanar drawings for all graphs with fixed edges
always positive instances for SEFE
always positive instances for SEFE two caterpillars (in polynomial area) [Brass et al. ’06]
always positive instances for SEFE two caterpillars (in polynomial area) [Brass et al. ’06] a planar graph and a tree [Frati ’06]
always positive instances for SEFE two caterpillars (in polynomial area) [Brass et al. ’06] counterexamples for SEFE a planar graph and a tree [Frati ’06]
always positive instances for SEFE two caterpillars (in polynomial area) [Brass et al. ’06] counterexamples for SEFE three paths [Brass et al. ’06] a planar graph and a tree [Frati ’06]
always positive instances for SEFE two caterpillars (in polynomial area) [Brass et al. ’06] counterexamples for SEFE three paths [Brass et al. ’06] a planar graph and a tree [Frati ’06] two outerplanar graphs [Frati ’06]
always positive instances for SEFE two caterpillars (in polynomial area) [Brass et al. ’06] counterexamples for SEFE three paths [Brass et al. ’06] a planar graph and a tree [Frati ’06] two outerplanar graphs [Frati ’06] SEFE testable in O(n2) time for two biconnected planar graphs with connected intersection
[Bl¨ asius & Rutter ’16]
always positive instances for SEFE two caterpillars (in polynomial area) [Brass et al. ’06] counterexamples for SEFE three paths [Brass et al. ’06] Variants a planar graph and a tree [Frati ’06] two outerplanar graphs [Frati ’06] SEFE testable in O(n2) time for two biconnected planar graphs with connected intersection
[Bl¨ asius & Rutter ’16]
always positive instances for SEFE two caterpillars (in polynomial area) [Brass et al. ’06] counterexamples for SEFE three paths [Brass et al. ’06] Variants no fixed mapping between vertices [Brass et al. ’06] a planar graph and a tree [Frati ’06] two outerplanar graphs [Frati ’06] SEFE testable in O(n2) time for two biconnected planar graphs with connected intersection
[Bl¨ asius & Rutter ’16]
always positive instances for SEFE two caterpillars (in polynomial area) [Brass et al. ’06] counterexamples for SEFE three paths [Brass et al. ’06] Variants no fixed mapping between vertices [Brass et al. ’06] a planar graph and a tree [Frati ’06] two outerplanar graphs [Frati ’06] geometric simultaneous embedding (GSE) [Angelini et al. ’11, Di Giacomo et al. ’15] SEFE testable in O(n2) time for two biconnected planar graphs with connected intersection
[Bl¨ asius & Rutter ’16]
quasiplanar GSE
quasiplanar GSE a tree and a cycle [Didimo et al. ’12]
quasiplanar GSE a tree and a cycle [Didimo et al. ’12] a tree and an outerpillar [Di Giacomo et al. ’15]
quasiplanar GSE a tree and a cycle [Didimo et al. ’12] a tree and an outerpillar [Di Giacomo et al. ’15] not every two quasiplanar graphs [Di Giacomo et al. ’15]
quasiplanar GSE simultaneous RAC drawings [Argyriou et al. ’13, Bekos et al. ’16, Evans et al. ’16, Grilli ’18] a tree and a cycle [Didimo et al. ’12] a tree and an outerpillar [Di Giacomo et al. ’15] not every two quasiplanar graphs [Di Giacomo et al. ’15]
always positive instances for QuaSEFE
always positive instances for QuaSEFE two planar graphs and a tree
always positive instances for QuaSEFE two planar graphs and a tree a 1-planar graph and a planar graph
always positive instances for QuaSEFE two planar graphs and a tree a 1-planar graph and a planar graph planar graphs with restrictions on their intersection graphs
always positive instances for QuaSEFE two planar graphs and a tree a 1-planar graph and a planar graph planar graphs with restrictions on their intersection graphs counterexamples for QuaSEFE in two special settings
G1 T2 G3
G1 T2 G3
G1 T2 G3
G1 T2 G3
some edges fixed by G1
G1 T2 G3
some edges fixed by G1 choose planar rotation system from G3 for edges in G3 \ G1 v u1 v u1 u2 u2 u3 u3 u4 u4
G1 T2 G3
some edges fixed by G1 choose planar rotation system from G3 for edges in G3 \ G1 v u1 v u1 u2 u2 u3 u3 u4 u4 u4
G1 T2 G3
some edges fixed by G1 choose planar rotation system from G3 for edges in G3 \ G1 v u1 v u1 u2 u2 u3 u3 u4 u4
G1 T2 G3
some edges fixed by G1 choose planar rotation system from G3 for edges in G3 \ G1
G1 T2 G3
some edges fixed by G1 choose planar rotation system from G3 for edges in G3 \ G1 remaining edges embedded planar
G1 T2 G3
some edges fixed by G1 choose planar rotation system from G3 for edges in G3 \ G1 remaining edges embedded planar
G1 T2 G3
some edges fixed by G1 choose planar rotation system from G3 for edges in G3 \ G1 remaining edges embedded planar
G3 \ G1 planar
G1 T2 G3
some edges fixed by G1 choose planar rotation system from G3 for edges in G3 \ G1 remaining edges embedded planar
G3 \ G1 planar
G1 T2 G3
some edges fixed by G1 choose planar rotation system from G3 for edges in G3 \ G1 remaining edges embedded planar
G3 \ G1 planar
G1 T2 G3
some edges fixed by G1 choose planar rotation system from G3 for edges in G3 \ G1 remaining edges embedded planar
G3 \ G1 planar thickness 2 ⇒ quasiplanar
G1 T2 G3
some edges fixed by G1 choose planar rotation system from G3 for edges in G3 \ G1 remaining edges embedded planar
G3 \ G1 planar thickness 2 ⇒ quasiplanar
and a forest T2 [Ackerman ’14]
and a forest T2 [Ackerman ’14]
Let G1, G2 and G3 planar graphs on V
Let G1, G2 and G3 planar graphs on V H1 H2 H3 H1,2 H2,3 H H1,3
Let G1, G2 and G3 planar graphs on V Theorem: If G1 \ G3, G2 \ G3 admits a SEFE, G1, G2, G3 admits a QuaSEFE. H1 H2 H3 H1,2 H2,3 H H1,3
Let G1, G2 and G3 planar graphs on V Theorem: If G1 \ G3, G2 \ G3 admits a SEFE, G1, G2, G3 admits a QuaSEFE. H1 H2 H3 H1,2 H2,3 H H1,3
Let G1, G2 and G3 planar graphs on V Theorem: If G1 \ G3, G2 \ G3 admits a SEFE, G1, G2, G3 admits a QuaSEFE. H1 H2 H3 H1,2 H2,3 H H1,3
Let G1, G2 and G3 planar graphs on V Theorem: If G1 \ G3, G2 \ G3 admits a SEFE, G1, G2, G3 admits a QuaSEFE. H1 H2 H3 H1,2 H2,3 H H1,3
Let G1, G2 and G3 planar graphs on V Theorem: If G1 \ G3, G2 \ G3 admits a SEFE, G1, G2, G3 admits a QuaSEFE. H1 H2 H3 H1,2 H2,3 H H1,3
Let G1, G2 and G3 planar graphs on V Theorem: If G1 \ G3, G2 \ G3 admits a SEFE, G1, G2, G3 admits a QuaSEFE. H1 H2 H3 H1,2 H2,3 H Corollary: H1 = ∅ ⇒ QuaSEFE H1,3
Let G1, G2 and G3 planar graphs on V Theorem: If G1 \ G3, G2 \ G3 admits a SEFE, G1, G2, G3 admits a QuaSEFE. H1 H2 H3 H1,2 H2,3 H Corollary: H1 = ∅ ⇒ QuaSEFE H1,3
Let G1, G2 and G3 planar graphs on V Theorem: If G1 \ G3, G2 \ G3 admits a SEFE, G1, G2, G3 admits a QuaSEFE. H1 H2 H3 H1,2 H2,3 H Corollary: H1 = ∅ ⇒ QuaSEFE H1,3 Corollary: H1,2 is forest of paths ⇒ QuaSEFE
Let G1, G2 and G3 planar graphs on V Theorem: If G1 \ G3, G2 \ G3 admits a SEFE, G1, G2, G3 admits a QuaSEFE. H1 H2 H3 H1,2 H2,3 H Corollary: H1 = ∅ ⇒ QuaSEFE H1,3 Corollary: H1,2 is forest of paths ⇒ QuaSEFE Theorem: If H is a forest of paths, G1, G2, G3 admits a QuaSEFE.
Sunflower Instance: Planar Graphs G1, . . . , Gk s.t. each edge is either in exactly one Gi or in all Gi (i.e. in H := Gi)
Sunflower Instance: Planar Graphs G1, . . . , Gk s.t. each edge is either in exactly one Gi or in all Gi (i.e. in H := Gi) Deciding if SEFE exists is NP-hard for k ≥ 3 [Angelini et al. ’15] [Schaefer ’13]
Sunflower Instance: Planar Graphs G1, . . . , Gk s.t. each edge is either in exactly one Gi or in all Gi (i.e. in H := Gi) Deciding if SEFE exists is NP-hard for k ≥ 3 [Angelini et al. ’15] [Schaefer ’13] Corollary: A sunflower instance with k = 3 planar graphs admits a QuaSEFE.
Sunflower Instance: Planar Graphs G1, . . . , Gk s.t. each edge is either in exactly one Gi or in all Gi (i.e. in H := Gi) Deciding if SEFE exists is NP-hard for k ≥ 3 [Angelini et al. ’15] [Schaefer ’13] Theorem: For any k, a sunflower instance with k planar graphs admits a QuaSEFE. Corollary: A sunflower instance with k = 3 planar graphs admits a QuaSEFE.
Sunflower Instance: Planar Graphs G1, . . . , Gk s.t. each edge is either in exactly one Gi or in all Gi (i.e. in H := Gi) Deciding if SEFE exists is NP-hard for k ≥ 3 [Angelini et al. ’15] [Schaefer ’13] Theorem: For any k, a sunflower instance with k planar graphs admits a QuaSEFE.
Corollary: A sunflower instance with k = 3 planar graphs admits a QuaSEFE.
Sunflower Instance: Planar Graphs G1, . . . , Gk s.t. each edge is either in exactly one Gi or in all Gi (i.e. in H := Gi) Deciding if SEFE exists is NP-hard for k ≥ 3 [Angelini et al. ’15] [Schaefer ’13] Theorem: For any k, a sunflower instance with k planar graphs admits a QuaSEFE.
Corollary: A sunflower instance with k = 3 planar graphs admits a QuaSEFE.
Sunflower Instance: Planar Graphs G1, . . . , Gk s.t. each edge is either in exactly one Gi or in all Gi (i.e. in H := Gi) Deciding if SEFE exists is NP-hard for k ≥ 3 [Angelini et al. ’15] [Schaefer ’13] Theorem: For any k, a sunflower instance with k planar graphs admits a QuaSEFE.
each Gi is drawn with thickness 2 Corollary: A sunflower instance with k = 3 planar graphs admits a QuaSEFE.
Theorem: There are two matchings M1 and M2 that do not admit a QuaSEFE for a fixed drawing of M1.
Theorem: There are two matchings M1 and M2 that do not admit a QuaSEFE for a fixed drawing of M1. v3 v5 v6 v7 v9 v11 v12 v13 v16 v17 v19 v18 v20 v1 v2 v15 v4 v14 v10 v8
Theorem: There are two matchings M1 and M2 that do not admit a QuaSEFE for a fixed drawing of M1. v3 v5 v6 v7 v9 v11 v12 v13 v16 v17 v19 v18 v20 M2 = M1 \ {(v17, v18), (v19, v20)} ∪ {(v18, v20)} v1 v2 v15 v4 v14 v10 v8
Theorem: There are two matchings M1 and M2 that do not admit a QuaSEFE for a fixed drawing of M1. v3 v5 v6 v7 v9 v11 v12 v13 v16 v17 v19 v18 v20 M2 = M1 \ {(v17, v18), (v19, v20)} ∪ {(v18, v20)} v1 v2 v15 v4 v14 v10 v8
Theorem: There are two matchings M1 and M2 that do not admit a QuaSEFE for a fixed drawing of M1. v3 v5 v6 v7 v9 v11 v12 v13 v16 v17 v19 v18 v20 M2 = M1 \ {(v17, v18), (v19, v20)} ∪ {(v18, v20)} v1 v2 v15 v4 v14 v10 v8
Theorem: There are two matchings M1 and M2 that do not admit a QuaSEFE for a fixed drawing of M1. v3 v5 v6 v7 v9 v11 v12 v13 v16 v17 v19 v18 v20 M2 = M1 \ {(v17, v18), (v19, v20)} ∪ {(v18, v20)} v1 v2 v15 v4 v14 v10 v8
Theorem: There are two matchings M1 and M2 that do not admit a QuaSEFE for a fixed drawing of M1. v3 v5 v6 v7 v9 v11 v12 v13 v16 v17 v19 v18 v20 M2 = M1 \ {(v17, v18), (v19, v20)} ∪ {(v18, v20)} v1 v2 v15 v4 v14 v10 v8
Theorem: There are two matchings M1 and M2 that do not admit a QuaSEFE for a fixed drawing of M1. v3 v5 v6 v7 v9 v11 v12 v13 v16 v17 v19 v18 v20 M2 = M1 \ {(v17, v18), (v19, v20)} ∪ {(v18, v20)} v1 v2 v15 v4 v14 v10 v8
Theorem: There are two matchings M1 and M2 that do not admit a QuaSEFE for a fixed drawing of M1. v3 v5 v6 v7 v9 v11 v12 v13 v16 v17 v19 v18 v20 M2 = M1 \ {(v17, v18), (v19, v20)} ∪ {(v18, v20)} v1 v2 v15 v4 v14 v10 v8
Theorem: There are two matchings M1 and M2 that do not admit a QuaSEFE for a fixed drawing of M1. v3 v5 v6 v7 v9 v11 v12 v13 v16 v17 v19 v18 v20 M2 = M1 \ {(v17, v18), (v19, v20)} ∪ {(v18, v20)} v1 v2 v15 v4 v14 v10 v8
Do the following always admit a QuaSEFE?
Do the following always admit a QuaSEFE? two 1-planar graphs
Do the following always admit a QuaSEFE? two 1-planar graphs a quasiplanar graph and a matching
Do the following always admit a QuaSEFE? two 1-planar graphs a quasiplanar graph and a matching three outerplanar graphs
Do the following always admit a QuaSEFE? two 1-planar graphs a quasiplanar graph and a matching three outerplanar graphs four paths
Do the following always admit a QuaSEFE? two 1-planar graphs a quasiplanar graph and a matching three outerplanar graphs four paths What is the computational complexity of QuaSEFE?
Do the following always admit a QuaSEFE? two 1-planar graphs a quasiplanar graph and a matching three outerplanar graphs four paths What is the computational complexity of QuaSEFE? Extend to other beyond planar graph classes such as k-planar graphs.
Do the following always admit a QuaSEFE? two 1-planar graphs a quasiplanar graph and a matching three outerplanar graphs four paths What is the computational complexity of QuaSEFE? Extend to other beyond planar graph classes such as k-planar graphs. Main difficulty: find a similarly catchy name for the problem
Do the following always admit a QuaSEFE? two 1-planar graphs a quasiplanar graph and a matching three outerplanar graphs four paths What is the computational complexity of QuaSEFE? Extend to other beyond planar graph classes such as k-planar graphs. Main difficulty: find a similarly catchy name for the problem