The 2-distance coloring of graph G is a proper vertex coloring such that no two vertices at distance less than or equal to 2 in G are assigned the same color.

The 2-distance coloring of a graph G is a proper vertex coloring such that no two vertices at distance less than or equal to 2 in G are assigned the same color.

The 2-distance coloring of graph G(V,E) means a proper vertex coloring such that no two vertices at distance less than or equal to 2 in G were assigned the same color.

The 2-distance chromatic number of Cartesian product of graphs;

2-distance chromatic number of weak direct product graphs

We obtained a lower bound of 2-distance chromatic number of family of graphs with maximum degree Δ,χ2(Δ=d)≥(d2+1)2,d≡0(mod 2)(d+1)(d+3)4,d≡1(mod 2)We have also answered a question which was stated in [1]: for any graph G, does there exist a constant C such that χ2(G)≤CΔ(G)? We have proved the constant C is not existent.

A study of industrial classification and green gap based on the energy-saving and emissions-reducing in Shandong Province

This paper takes four indices : energy consumption,water resource consumption,the emissions of COD and SO_2 of every ten thousand yuan GDP as the basis to establish two comprehensive indices: green gap and green contribution,which are the embodiment of harmonious d.

According to the standard of national ecology city,four indexes of Xi an city-energy consumption,water consumption,the emissions of COD and SO2 of one thousand industrial output in 1985-2005 are chosen and their green gap and ecology realization degree are appraised.

The goal is to conquer the fault that the Euclidean distance in the traditional cylindrical coordinates cannot reasonably discriminate different colors once the color value is widely different By altering image s luminance based on its situation veracity of the color distance model is improved.