#contradictory  two propositions are contradictories if both cannot be true (or both cannot be false) at the same time
  supertype:  logical_relation__logicalrelation  a relation between logical propositions
     supertype:  relation  an abstraction belonging to or characteristic of two entities or parts together
        supertype:  thing_that_can_be_seen_as_a_relation  usable as relation type
           supertype:  thing_playing_some_role  category to classify things according to roles/viewpoints; classification under this category is application-dependant
              supertype:  thing__something___T__t___3D_or_4D_thing_or_anything_else  any category (type or individual) is instance of this type; any type is also a subtype of this type

No statement uses or specializes contradictory; click here to add one.