Empty tree in problem 3.2

Master / Vertiefung Künstliche Intelligenz
1

Disclaimer: Dieser Thread wurde aus dem alten Forum importiert. Daher werden eventuell nicht alle Formatierungen richtig angezeigt. Der ursprüngliche Thread beginnt im zweiten Post dieses Threads.

2

Empty tree in problem 3.2
Unfortunately I don’t quite understand how the empty tree with no nodes should be represented in the definition of trees in problem 3.2, for reference:

subtrees([]).
istree(tree(Value,Children)) :− string(Value),subtrees(Children).
subtrees([(Cost,T)|Rest]) :− number(Cost),istree(T), subtrees(Rest).

Can anyone help?

3

You can make a tree with just the root node “A” and no children like this:

tree("A",[])

I hope this helps.

You can check out more examples in the notebook:
https://swish.swi-prolog.org/example/lists.pl
Since Swish is being particularly unreliable this year, I’ll also post the code from the notebook to
https://kwarc.info/teaching/AI/resources/