[wormik]

https://mathworld.wolfram.com/Tree.html

https://www.math.ru.nl/OpenGraphProblems/TimV/notationsandde...

[phaemon]

Thank you, but I know what a tree is. I believe they were specifically referring to https://treenotation.org/

That's the thing I hadn't heard of and would be interested to hear if someone had tried applying it in real world scenarios.