Conservation Rules of Direct Sum Decomposition of Groups - Formalized Mathematics - Tom 24, Numer 1 (2016) - DML-PL - Yadda2016 | 24 | 1 | 81-94Kazuhisa Nakasho ,	Hiroshi Yamazaki ,	Hiroyuki Okazaki ,	Yasunari Shidamagroup theory direct sum decomposition10.1515/forma-2016-0007bwmeta1.element.doi-10_1515_forma-2016-0007
