出典:Wiktionary
出典:『Wiktionary』 (2015/07/17 16:23 UTC 版)
multitree (複数形 multitrees)
出典:Wikipedia
出典:『Wikipedia』 (2011/05/19 23:05 UTC 版)
In combinatorics and order-theoretic mathematics, a multitree may describe either of two equivalent structures: a directed acyclic graph in which the set of nodes reachable from any node form a tree, or a partially ordered set (also called a diamond-free poset) that does not have four items a, b, c, and d forming a diamond suborder with a ≤ b ≤ d and a ≤ c ≤ d but with b and c incomparable to each other.