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*Proposition:* For proving with knowledge `K` the goal
**exists** `x`: `G`,
it suffices to prove `G`[`x` <- `T`]
for some term `T`.

~~>

Kexistsx:G

KG[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*.

Author: Wolfgang Schreiner

Last Modification: November 30, 1999