I believe I once had a proof of this proposition, but it's been lost to the mists of time and old hard drives, so who knows if it was correct, and try as I might I can't seem to reproduce it.
Is it possible, in Melliès' tensorial logic, to give a proof of ¬(¬⊤¬1 ⊗ ¬⊤¬1) (a.k.a. ⊤1 ⅋ ⊤1)? Equivalently, is there an arrow in a dialogue category (with monoidal unit ⊤1 and negation functor ¬) from ¬⊤¬1 to ⊤1?