MathDB
k flowing chromatic

Source: 2017 China TST 5 P6

April 14, 2017
graph theorycombinatorics

Problem Statement

We call a graph with n vertices kflowingchromatick-flowing-chromatic if: 1. we can place a chess on each vertex and any two neighboring (connected by an edge) chesses have different colors. 2. we can choose a hamilton cycle v1,v2,,vnv_1,v_2,\cdots , v_n, and move the chess on viv_i to vi+1v_{i+1} with i=1,2,,ni=1,2,\cdots ,n and vn+1=v1v_{n+1}=v_1, such that any two neighboring chess also have different colors. 3. after some action of step 2 we can make all the chess reach each of the n vertices. Let T(G) denote the least number k such that G is k-flowing-chromatic. If such k does not exist, denote T(G)=0. denote χ(G)\chi (G) the chromatic number of G. Find all the positive number m such that there is a graph G with χ(G)m\chi (G)\le m and T(G)2mT(G)\ge 2^m without a cycle of length small than 2017.