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*Proposition:*
For proving with knowledge `K` union {**forall** `x`: `F`}
the goal `G`, it suffices to prove
`G` with additional knowledge `F`[`x` <- `T`] for any term `T`:

~~>

Kunion {forallx:F}G

Kunion {forallx:F,F[x<-T]}G

"We have to prove `G`. Since we know (**forall** `x`: `F`), we
have `F`[`x` <- `T`] and thus ...(proof of
`G` with additional knowledge `F`[`x` <- `T`])."

*A formula ( forall x: F) in the knowledge is a machine
that takes any T and produces additional knowledge F[x
<- T].*

Author: Wolfgang Schreiner

Last Modification: November 30, 1999