On the Enumeration of Interval Graphs
نویسندگان
چکیده
We present upper and lower bounds for the number in of interval graphs on n vertices. Answering a question posed by Hanlon, we show that the ordinary generating function I(x) = ∑ n≥0 in x n for the number in of n-vertex interval graphs has radius of convergence zero. We also show that the exponential generating function J(x) = ∑ n≥0 in x n/n! has radius of convergence at least 1/2.
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تاریخ انتشار 2017