关于密度函数公式的注记

给出了Z=X^2/a^2＋Y^2/b^2,Z=X^2/a^2-Y^2/b^2,Z=√X^2/a^2＋Y^2/b^2,Z=Y/aX^2的密度函数公式.     

关于数列部分和子列的一个注记

以b1,b2…,bn,…表示数列a1,1,a1,2,…,a1,m1,a2,1,a2,2,…,a2,m2,…,ai,1,ai,2,…,ai,mi,…,给出了n∑i=1bi与n∑i=1mi∑k=1ai,k的一个关系.给出了几个应用实例.     

An Historical Note on the Origins of Probabilistic Indexing

The motivation behind “Probabilistic Indexing” was to replace two-valued thinking about information retrieval with probabilistic notions. This involved a new view of the information retrieval problem – viewing it as problem of inference and prediction, and introducing probabilistically weighted indexes and probabilistically ranked output. These ideas were first formulated and written up in August 1958.     

关于空间图形"对称性"的注记

推广了现行空间解析几何教材中空间图形关于“坐标原点，一坐标平面，坐标轴”的对称性定理。