报告人：You Lu

Department of Applied Mathematics, School of Science,

Northwestern Polytechnical University

摘要：

The well-known Bouchet’s conjecture is that every s-bridgeless signed graph admits a nowhere-zero integer 6-flow. The best published result belongs to Zyka who proved the conjecture with 6 replaced by 30. Recently, DeVos proved that every s-bridgless signed graph admits a nowhere-zero balanced Z 2 × Z 3 -flow, and thus admits a nowhere-zero 12-flow. In this talk, we further strengthen DeVos’s result to 11-flow for bridgeless signed graphs by generalizeing two known results due to Xu and Zhang, and then verified the conjecture for all signed graphs without two edge-disjoint unbalanced circuits.