<blockquote> an exposition on the great utility of using the parent-index method of representing trees in J. </blockquote> This is similar, but with K and less comprehensive: <a href=“https://github.com/JohnEarnest/ok/blob/gh-pages/docs/Trees.md” rel=“ugc”>https://github.com/JohnEarnest/ok/blob/gh-pages/docs/Trees.md</a> Comments