I'm a bit new to predicate logic derivations and their rules and I'm having a bit of trouble working something out. It is as follows:
$\forall x Fx \therefore \exists x Fb(x)$
I'm told I cannot use any form of $QN$, so my first step is to use $UI$ on the first predicate to get: $Fb$, but I'm just stuck on what to do next.
Any help would be appreciated, thanks.
I assume $b$ is a function?
If so, use UI to get $Fb(a)$, and then use EG to get $\exists x Fb(x)$