5 papers
A study on parity signed graphs: the number
Ligang Jin, Xiaoyue Chen, Yingli Kang
The study on parity signed graphs was initiated by Acharya and Kureethara very recently and then followed by Zaslavsky etc.. Let be a signed graph on vertices. If $(G,σ…
Partially normal 5-edge-colorings of cubic graphs
Ligang Jin, Yingli Kang
In a proper edge-coloring of a cubic graph, an edge is normal if the set of colors used by the edges adjacent to has cardinality 3 or 5. The Petersen coloring conjecture as…
Colouring of generalized signed planar graphs
Ligang Jin, Tsai-Lien Wong, Xuding Zhu
Assume is a graph. We view as a symmetric digraph, in which each edge of is replaced by a pair of opposite arcs and . Assume is an inve…
Remarks on planar edge-chromatic critical graphs
Ligang Jin, Yingli Kang, Eckhard Steffen
The only open case of Vizing's conjecture that every planar graph with is a class 1 graph is . We give a short proof of the following statement: there is no 6-criti…
Plane graphs without 4- and 5-cycles and without ext-triangular 7-cycles are 3-colorable
Ligang Jin, Yingli Kang, Michael Schubert +1
Listed as No. 53 among the one hundred famous unsolved problems in [J. A. Bondy, U. S. R. Murty, Graph Theory, Springer, Berlin, 2008] is Steinberg's conjecture, which states that…