关于删除若干C-超边的完全一致混合超图色数的几个结论

Some Results on Chromatic Number of Uniform mixed Hypergraphs Obtained by Deleting Some C-hyperedges from a Complete Uniform Mixed Hypergraphs

混合超图的上、下色数与C-超边和D-超边数有着必然联系.一般地,增加C-超边会使下色数χ(H)增加,增加D-超边会使上色数-χ(H)减小.本论文以完全混合超图为例,进一步揭示C-超边数与上、下色数之间的关系,给出了完全一致混合超图κ(n,l,m)=(X,(Xl),(X在删除若干C-超边后其上、下色数的若干结论.

The upper chromatic number and lower chromatic number of mixed hypergraphs closely relacted with its C - hyperedgos and D -hyperedges. In general,adding one C -edges to can increase χ（￡） and adding one D-edge can decrease ^-χ（￡） ,where is a mixed hypergraph,χ（￡） is the lower chromatic number and ^-χ（￡） is the upper chromatic number of ￡. In this artical ,taking complete mixed hypergraphs as a example, further uncome the relation of that between the number of C - byperedges and D-hyperedges in ￡ and chromatic number of ￡, and give some results on upper chromatic unmber and lower chromatic number of uniform mixed hypergraphs ￡^1= （ X, （X/l）-C0, （X/m） ）, obtained by deleting some C - hyperedges from complete uniform mixed hypergraphs = （X,（X/l）,（X/m））, where Co is a subset of C.