Specification Gap

Specification gap refers to the mismatch that can exist between a formally stated claim and the informal intent it is supposed to capture. A proof assistant like Lean can rigorously verify that a proof establishes exactly what its formal statement says, but it has no way to confirm that statement is a faithful translation of the theorem or property the author actually meant to prove. This makes the gap a persistent risk in formal verification efforts: a fully checked proof can still be worthless if the formalization itself silently weakens, narrows, or misstates the original claim.