---
tag: 4N9JBQVG8V
kind: concept
name: Multitree
aliases: [mangrove-graph-theory, strongly-unambiguous-graph]
sources:
  - wikipedia: en:27131455@r1323981624
    locator: Multitree
    note: adopted
    mention: wikipedia://en/27131455
    sections: [Summary]
same_as:
  wikidata: Q6935120
  wikipedia: Multitree
inventory: [FK504Q0SP0]
---

## Summary

In [[combinatorics|0JKW7W7XFR]] and order theory, a **multitree** may describe either of two equivalent structures: a directed acyclic graph (DAG) in which there is at most one directed path between any two vertices, or equivalently in which the subgraph reachable from any vertex induces an [[undirected tree|062D9KXJB1]], or a [[partially ordered set|0QV2JS9RJ3]] (poset) that does not have four items $a$, $b$, $c$, and $d$ forming a diamond suborder with $a \le b \le d$ and $a \le c \le d$ but with $b$ and $c$ incomparable to each other (also called a **diamond-free poset**).