 | This article includes a list of references, related reading, or external links, but its sources remain unclear because it lacks inline citations. (January 2021) |
&sq=Qlik&lang=&file=File:Infinite_set-theoretic_tree.png)
In set theory, a tree is a partially ordered set (T, <) such that for each t ∈ T, the set {s ∈ T : s < t} is well-ordered by the relation <. Frequently trees are assumed to have only one root (i.e. minimal element), as the typical questions investigated in this field are easily reduced to questions about single-rooted trees.