[Pharo-project] Collection arithmethic method category

In Pharo1.0 Collection organization listAtCategoryNamed: 'arithmethic' #() In PharoCore1.1 Collection organization listAtCategoryNamed: 'arithmetic' #(#* #+ #- #/ #'//' #'\\' #raisedTo:) And the arithmethic is not an extension of any Package. Why are all the methods in that category no present in PharoCore? How and when are they added into Pharo ? Fernando