Taxa with structural zero

[Bio2406839]

Hi! I have a question regarding this sentence in the tutorial: "A taxon is considered to have structural zeros in some (>=1) groups if it is completely (or nearly completely) missing in these groups."

I was wondering what is the abundance threshold in at least one group to assign a taxa with structural zero.

Thanks!

[simone-anza]

I think it's 0 if struc_zero = T, but can be also very close to 0 if neg_lb = T