Is it possible to unambiguously read back λ terms from interaction nets without node types?
So, yes, turns out it is possible, as can be seen on the decode function of my abstract algorithm implementation here. Basically, Lambda and Apply nodes are given the same tag (here, I use 0), and you can infer which is the case based on their positions. Each Duplication node, though, requires an unique tag. Note some terms such as (2 2) will reduce to a net which has Duplication nodes with the same tag. That is not an issue; when decoding, just treat anything with a tag different from 0 as a Duplication node.