Question: Clarification on Edge properties from FCI algo about causal-learn

[jdramsey]

I checked with Peter about the definition of "possibly direct"; the above is correct sfaik.

[kunwuz]

Thanks so much! This issue has just been solved in this PR by @zhi-yi-huang. Please let us know if there are any further questions.

[jdramsey]

These are from Tetrad PAG "graph coloring" and are as follows.

"nl" means "no latent"--i.e., this is a visible edge--i.e., if X->Y is marked as "nl" then there is no latent confounder for X and Y. This is an edge whose coefficient can be estimated.
"pl" means "possibly latent"--i.e., this is possibly not a visible edge.
"dd" means "definitely direct"--i.e., one can expect this edge to actually exist as a direct edge in the true DAG (with latents)
"pd" means "possibly direct"--i.e., this may go through other variables in the underlying DAG (with latents), like X->L1->...->Ln->Y for some latents L1, ..., Ln

[arainboldt]

Thanks a lot to both of you!