Go backward to Indirect Method for Universal Formulas Go up to Top Go forward to Typical Use |
Proposition: For proving with knowledge K the goal exists x: G, it suffices to prove G[x <- T] for some term T.
~~>
K exists x: G
K G[x <- T]
"We have to prove (exists x: G). We prove G[x <- T]".
We have to find a witness, i.e., a value for x that makes G true.