abstract DB = { 

cat
	Event;
	Location; 

fun

	-- anEvent : Event;
	meeting : Event;
	presentation : Event;
	date : Event;
	lecture : Event;

{-
	appointment : Event;
	class : Event;
	converence : Event;
	hairdresser : Event;
	dentist : Event;		
	party : Event;
	deadline : Event;
-}

	-- aLocation : Location;
	plaza : Location;
	station : Location;
	university : Location;
{-	
	fair : Location;
	ritz : Location;
	cafe : Location;
-}	



}