ีๆวฎีจฝ๐ปจ

ฑจธๆศหฃบณยาซฟก ฝฬสฺ

ฑจธๆสฑผไฃบ2017ฤ๊3ิย18ศี10:30--11:30

ฑจธๆตุตใฃบา�ท๒ยฅ701

ฑจธๆีชาชฃบA fractional coloring of a graphGis that we assign a nonnegative weight to each independent set inG, such that for each vertexvthe sum of the weights of the independent sets containingvis 1. The least sum of these weights is called the fractional chromatic number ofG, denoted by ฆึ*(G). Recently, Steinberg conjecture is disproved. It has been proved that every planar graph without 4-7-cycles is 3-colorable. Thus, one may ask whether every planar graph without 4-6-cycles is 3-colorable. In this talk, we will show that every planar graph without 4- and 6-cycles are 7/2-colorable and our result provides some support for the truth of this question.

ฑจธๆศหผ๒ฝ้ฃบ

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