Counting acyclic digraphs by sources and sinks
نویسندگان
چکیده
منابع مشابه
Counting acyclic digraphs by sources and sinks
We count labeled acyclic digraphs according to the number sources, sinks, and edges. 1. Counting acyclic digraphs by sources. Let An(t;α) = ∑ D αt, where the sum is over all acyclic digraphs D on the vertex set [n] = {1, 2, . . . , n}, e(D) is the number of edges of D, and s(D) is the number of sources of D; that is, the number of vertices of D of indegree 0. Let An(t) = An(t; 1). To find a rec...
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ژورنال
عنوان ژورنال: Discrete Mathematics
سال: 1996
ISSN: 0012-365X
DOI: 10.1016/0012-365x(95)00119-h