  We investigate the role of coalgebraic predicate logic, a logic for
neighborhood frames first proposed by Chang, in the study of monotonic modal
logics. We prove analogues of the Goldblatt-Thomason Theorem and Fine's
Canonicity Theorem for classes of monotonic neighborhood frames closed under
elementary equivalence in coalgebraic predicate logic. The elementary
equivalence here can be relativized to the classes of monotonic, quasi-filter,
augmented quasi-filter, filter, or augmented filter neighborhood frames,
respectively. The original, Kripke-semantic versions of the theorems follow as
a special case concerning the classes of augmented filter neighborhood frames.
