The Zettelkasten as a graph

Your note network has a treewidth, and it tells you something true.

Notes as vertices, links as edges

A Zettelkasten — a network of atomic notes connected by links — is a graph. Its treewidth measures how tree-like the network is: a low-width Zettelkasten can be reasoned over locally, branch by branch, while a high-width one has a densely interconnected core that resists being read in any linear order.

This is not a defect. The high-width regions are precisely where your thinking has found genuine, irreducible connection between ideas — the places no outline could capture because the structure is not a tree.

Reading the width

If a section of your notes has high treewidth, it is telling you that those ideas form an inseparable whole. The shadow–mirror reading: the tree-like periphery is the shadow you can decompose; the high-width core is the mirror, the coupling that has to be held all at once.