`Adj_mode_theory` Bitrot?

[Trebor-Huang]

There doesn't seem to be such a file, despite the claims in the comment of mode_theory.ml. I can sort of guess the implementation though. Is it deleted at some point or never written?

[jozefg]

Deleted I think. It refers to an earlier version of mitten which dealt with non-preordered mode theories where the adjoint mode theory was quite interesting. I think I have the code deciding the adjoint mode theory laying around somewhere if you're curious, but the rough idea is to capitalize on the equivalence between the walking adjunction and certain 2-categories of finite sets (see "The Free Adjunction" by Schanuel and Street)