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by colevee 692 days ago
Your intuition is right. The total functions are not even a provable set. So they are definitely not recursive or even FNP; never mind TFNP. Provability of the total functions would imply decidability of an even harder problem than the halting problem: whether a given Turing machine halts on _all_ inputs.

The halting problem only asks: given a TM and input, will the TM halt on that input? That problem is actually semi-decidable/provable: we just run the machine. If the answer is yes, then at some point it will halt!