src/HOL/Groups_List.thy
2014-09-18 haftmann 2014-09-18 product over monoids for lists
2014-09-11 haftmann 2014-09-11 abstract product over monoid for lists
2014-09-03 blanchet 2014-09-03 use 'datatype_new' in 'Main'
2014-08-31 haftmann 2014-08-31 separated listsum material