Odd or even on plane trees
نویسندگان
چکیده
منابع مشابه
Odd or even on plane trees
Over all plane trees with n edges, the total number of vertices with odd degree is twice the number of those with odd outdegree. Deutsch and Shapiro posed the problem of 3nding a direct two-to-one correspondence for this property. In this article, we give three di5erent proofs via generating functions, an inductive proof and a two-to-one correspondence. Besides, we introduce two new sequences w...
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ژورنال
عنوان ژورنال: Discrete Mathematics
سال: 2004
ISSN: 0012-365X
DOI: 10.1016/j.disc.2003.07.011