Description: Define the distance function component of a metric space (structure). (Contributed by NM, 4-Sep-2011) (Revised by Mario Carneiro, 14-Aug-2015) Use its index-independent form dsid instead. (New usage is discouraged.)
|- dist = Slot ; 1 2
|- dist
|- 1
|- 2
|- ; 1 2
|- Slot ; 1 2