Definition
Formal verification is the use of mathematical proof, checked by a machine, to establish that a system satisfies a precisely stated specification. In neural-network work it often means certifying a model’s arithmetic exhaustively over a finite set of inputs, such as a table of views, and encoding the resulting theorems in a proof assistant like Lean so that the kernel, not a reader, vouches for them. Unlike testing, which samples behavior, a verified claim covers every case in its stated scope—though it is only as strong as the specification and the model of the computation it assumes.