Propositional form X logically implies propositional form Y iff it is impossible for X to be true while Y is false.
Example from everyday life: 'x is six feet tall' logically implies 'x is at least five feet 10 inches tall'
Example from categorical logic: The conjunction of 'All M are P' and 'All S are M' logically implies 'All S are P'
Example from propositional logic: 'p • ~p' logically implies 'q'
Example from predicate logic: '(x)Øx' logically implies '(Ǝx)Øx' (on the assumption that at least one object exists)
