1. The first is about prepositional classification. In general logic, proposition consists of two categories, the simple proposition and the compound proposition. һ������ķ��ࣺ����ͨ���У�����ֳɼ���������������࣬������ֳ�ֱ�������ϵ�������֡�
2. A proposition on which another proposition depends; the antecedent of a conditional proposition. ǰ��Ϊ����һ���������������⣻
3. proposition system of expressing scientific knowledge����atomic proposition, molecularproposition, and generalized proposition; �����ѧ֪ʶ������ϵͳ����ԭ�����⡢��������������⣻
4. A proposition derived by negating and permuting the terms of another, equivalent proposition; for example, All not-Y is not-X is the contrapositive of All X is Y. ��λ�任�����ɷ��û���һ�ȼ����������õ������⣻���磬�����еķ�y�Ƿ�x���ǡ����е�x��y������λ�任���⡣
5. A proposition derived by negating and permuting the terms of another, equivalent proposition; for example, All not-Y is not-X is the contrapositive of All X is Y. ��λ�任�����ɷ��û���һ�ȼ����������õ������⣻���磬�����еķ�y�Ƿ�x���ǡ����е�x��y������λ�任���⡣