This is meant to be a fun question, and I hope it's not too off topic. Is there a defined mathematical object or data structure that has a name collision with a type of physical tree in the real world?

In computer science we have red-black trees, B-trees, quadtrees, and so on. In the biological sense of the word tree, we have palm trees, pine trees, redwood trees, etc.

My question: is there a word $w$ such that a $w$ tree could refer to a physical tree in the real world, or a mathematical object?

  • $\begingroup$ I would give aspen tree as an answer, except that the structure that the authors describe isn't actually a tree. conferences.sigcomm.org/co-next/2013/program/p85.pdf $\endgroup$
    – Joe
    Commented Jun 3, 2014 at 17:06
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    $\begingroup$ It's not quite what you want, but there is a graph-theoretic cactus. $\endgroup$ Commented Jun 3, 2014 at 17:16
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    $\begingroup$ I guess "rooted tree" does not count? $\endgroup$
    – Raphael
    Commented Jun 3, 2014 at 21:32
  • $\begingroup$ This doesn't answer your question either, but this paper borrows liberally from the terminology of forestry management in the service of managing trees, in a typical Phil Wadler way. homepages.inf.ed.ac.uk/wadler/topics/deforestation.html $\endgroup$
    – Pseudonym
    Commented Jun 4, 2014 at 2:01
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    $\begingroup$ I was sorry to find out that people using attributed grammars do not even call Xmas trees their trees decorated with attributes. $\endgroup$
    – babou
    Commented Jun 4, 2014 at 13:25

2 Answers 2


Robert Tarjan defines the palm tree in "Depth-first search and linear graph algorithms" (1972):

Let $P$ be a directed graph of two disjoint edge sets, denoted $v \rightarrow w$ and $v \overset{-}{\rightarrow} w$ respectively. If $P$ satisfies the following properties:

  1. The subgraph $T$ containing the edges $v \rightarrow w$ is a spanning tree of $P$;

  2. Each edge not in $T$ connects a vertex with one of its ancestors in $T$. The edges $v \overset{-}{\rightarrow} w$ are called the fronds of $P$.


Palm Tree

He goes on to prove that the directed graph generated by a depth-first search of a connected graph is a palm tree.

In Collective Tree Spanners and Routing in AT-free Related Graphs, Dragan, Yan, and Corneil construct a specific spanning tree that they call a willow-tree.


How about a banana tree? The organic kind are colloquially, but not botanically, trees.


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