By decomposing the space of contact forces into four subspaces, a general formulation of contact forces is developed. 通过将接触力空间分解成四个子空间，给出了接触力的一般表达式。
A construction of authentication codes with arbitration from subspaces of singular symplectic geometry over finite fields is presented, the parameters of the code are computed. 摘要利用有限域上奇异辛几何的子空间构造了一个具有仲裁的认证码，并计算了这个码的参数。
