Thor Johnson
Princeton University
5 Papers
43 Citations
Thor Johnson is an academic researcher from Princeton University. The author has contributed to research in topics: Complement graph & Cubic graph. The author has an hindex of 5, co-authored 5 publications.
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Papers
Directed Tree-Width
TL;DR: It is proved that every directed graph with no “haven” of large order has small tree-width, and the Hamilton cycle problem and other NP-hard problems can be solved in polynomial time when restricted to digraphs of bounded tree- width.
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Spanning trees with many leaves
TL;DR: In this paper, it was shown that if G is a simple connected graph with $$|E\;({\bf G})|\geq |V\;(\,G)|+{1 \over 2}t\,\;(t-1)$$ and $|V(G)| \,
eq\,t+2$, then G has a spanning tree with
234
Generating Internally Four-Connected Graphs
Thor Johnson,Robin Thomas +1 more
TL;DR: It is proved that if H and G are internally 4-connected graphs such that they are not isomorphic, H is a minor of G, and they do not belong to a family of exceptional graphs, then there exists a graph H?
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•Posted Content
Excluding A Grid Minor In Planar Digraphs.
TL;DR: The conjecture that a digraph of huge tree-width has a large "cylindrical grid" minor is proved, not only for planar digraphs, but many steps of the proof work in general.
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Cut Coloring and Circuit Covering
Matt DeVos,Thor Johnson,Paul Seymour +2 more
- 01 Jan 2006
TL;DR: For every 3-edge-connected graph G and every map p : E(G) → {84, 86, 86], there exists a multiset of circuits of G such that every edge e ∈ E ∈ G is contained in exactly p(e) of these circuits.
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