Fig. 2
From: Path homologies of motifs and temporal network representations
(Center) The digraph \(D_2\) has trivial path homology but the digraph \(D_1\) does not. (Left) The nontrivial path homology of \(D_1\) can be interpreted as a consistent and robust unidirectional flow. (Right) The trivial path homology of \(D_2\) can be attributed to w and z appearing as “bottlenecks” that prevent robustness of the flow. This intuition is formalized by results in Chowdhury et al. (2019)