This is a preview. Log in through your library . Abstract A propositional system of modal logic is second-order if it contains quantifiers ∀p and ∃p, which, in the standard interpretation, are ...

This is a preview. Log in through your library . Abstract We construct an extension $\scr{L}^{P}$ of the standard language $\scr{L}$ of classical propositional logic by adjoining to the alphabet of ...

We are hardly ever consciously aware that we use logic to solve everyday problems. But what is logic? Is the logic used to prove theorems in mathematics the same kind that we use for our practical ...