We also prove the following properties : the stable states of the network in the same sh orbit have a same dynamical behavior , such as the size of attraction basin and the energy ; the relation of the symmetry of two isometric networks h and h ' = g - h is s ' h = g - sh - g ~ } for any isometry g , where sh and s ' h are the symmetry of h and h " respectively ; the isometry will not change the dynamical properties of the stable states set of the corresponding networks ; etc . ) g的对称性s _ h和s _ n的关系为s _ h = g ? s _ h ? g ~ ( - 1 ) ；等距变换不会改变网络稳定态集的动力学性质等一系列的结论。所有这些研究结果表明了hebb学习法则是通过调整网络的连接矩阵，使得其的结构的对称性包含存储样本集的对称性这一存储机理。
Part four brings forward the suggestions on the realistic select of the rural pension security system , namely " the home care and the individual ' s self - security play the main role , extruding individual responsibility , and the state sets up the lowest living security system as well as providing manifold social sustain measures . 第四部分针对我国大多数农村的现状，提出中国农村养老保障模式的现实选择。即“家庭及个人自我保障为主、突出个人责任，国家提供最低生活保障制度，辅之以多种社会支持”的保障模式。
