Abstract
In this paper, we give some new properties of edge chromatic critical graphs, and give new lower bounds for the average degree of Δ-critical graphs with Δ=11, 12 by the use of these properties.
2000 AMS Subject Classification:
Acknowledgements
The authors would like to express their thanks to the referee for his valuable corrections and suggestions of the manuscript that greatly improve the format and correctness of it. Lian-Ying Miao was supported by Fundamental Research Funds for the Central Universities (2012LWB46) and National Natural Science Foundation of China (11271365). Zheng-Ke Miao was supported by National Natural Science Foundation of China (11171288).