The Crossing Number of a Projective Graph is Quadratic in the Face-Width
نویسندگان
چکیده
We show that for each integer g ≥ 0 there is a constant cg > 0 such that every graph that embeds in the projective plane with sufficiently large face–width r has crossing number at least cgr 2 in the orientable surface Σg of genus g. As a corollary, we give a polynomial time constant factor approximation algorithm for the crossing number of projective graphs with bounded degree.
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ورودعنوان ژورنال:
- Electronic Notes in Discrete Mathematics
دوره 29 شماره
صفحات -
تاریخ انتشار 2007