[nynox]

Following this proof tree idea, this recent paper https://arxiv.org/abs/2102.03044 suggests to think of proofs of theorems as large trees, a tiny subset of which needs to be made explicit to convey the confidence the rest could be written out (if ever needed).

[carapace]

Does that presuppose that it's computationally expensive to verify proofs? If so, isn't that kind of unrealistic?

[nynox]

Verifying fully formalized proofs is cheap. What is expensive is to produce such formalized proofs. More precisely, to formalize a proof written in a typical math paper is extremely time-consuming and not so informative (that's why it's almost never done in practice).