VF2 | This is a simple implementation of the VF2 algorithm

If your list is called list_df you can try :

Your premises of m3$modelStruct$varStruct being a named vector is incorrect. Your multiplication returns an object of

Just use LAG:

You are almost there. As far as concerns, you just need to fix the subquery:

• it needs to be correlated to the outer query

• you can't nest aggregate expressions, like MAX(COUNT(*)); that would require a additional level of aggregation - instead, you can order by and limit

I would suggest:

Answering my own question after many hours of sorrow. I was hoping this was going to be an interesting technical question. Turns out it's just a run-of-the-mill nomenclature question!

NetworkX defines a subgraph isomorphism as the following:

If G'=(N',E') is a node-induced subgraph, then:

• N' is a subset of N
• E' is the subset of edges in E relating nodes in N'

(Taken from networkx inline code comments.)

It defines a mono​morphism as the following:

If G'=(N',E') is a monomorphism, then:

• N' is a subset of N
• E' is a subset of the set of edges in E relating nodes in N'

And further, notes:

Note that if G' is a node-induced subgraph of G, then it is always a subgraph monomorphism of G, but the opposite is not always true, as a monomorphism can have fewer edges.

In other words, because there are other edges involved in this graph than are described by the G2 graph, the DiGraphMatcher considers the set of edges E' to be not equal to the subset of edges in E relating nodes in N'.

Instead, the edges in E' are a subset of the set of edges in E relating nodes in N', and so networkx calls this a monomorphism instead.

To better illustrate this point, consider the following: