【关於原本有向图】苗正科.pdf
学 号:DG9721007 论文答辩日期:20年上月20日 指导教师:(签字)
Acknowledgments I would liketo thank my supervisor,Professor.ZhangKeMin,for his introducingmetoCombinatorialTheoryandGraphTheory,generous help,valuable suggestions,consistent availability and carefulattention to the details of my thesis.
R;(X) set ofvertices reached from X by a walk of length i.u.v[k] thereis awalkoflengthkfrom vertexu tovertexuin a digraph uu[k] there is no walk of lengthk from vertex u to vertexv in a digraph u.u[D] anywalkfrom vertex u tovertexu inD L(D) set of lengths of cycles in D