Take the semantic definition of existential and universal qualifier outlined here
Is that valid for classical or intuitionistic logic? Or is it a general definition?
Take the following sentence:
"It exists a man that, if he owns an hat, then all mans own an hat"
Take $C(x)$ is the predicate:
"Man $x$ owns an hat"
than the sentence can be formally written as follow:
$\exists x(C(x) \rightarrow \forall xC(x)) $
How can that sentence be semantically interpreted using the initial definition of existential and universal qualifier?