Assertion: tree's structure | /r/HasProperty | unordered tree
Facets:
Source sentences:
text: Then the structure (ℱ, ⊆) is an unordered tree whose root equals U. Conversely, if (U, ≤) is an unordered tree, and ℱ is the set {↓x | x ∈ U} of all principal ideals of (U, ≤) then the set system (U, ℱ) satisfies the above properties.
text: Apparently, the structure (X'‌, R'‌) is an unordered tree in the "partial-algebra" version: