本文的主要目的是给出投射模的一个特征性质,从而说明1984年A.K.Tiwary等人关于伪投射模的一个结果是不成立的.此外,本文给出了投射模、半单模以及伪投射模之间的一些关系,并用伪投射模给出了半单环的一个特征性质.
An R-module M is called pseudo-projective if for any Riven R-module A. and epimorphistns f,g:M→A there exists a homeinorphisin h:AI→M such that f=gh. In 1984, A.K.Tiwary et al. proved that: a module M is pseudo-projective inf for any given R-Modules A.N.epimorphisms f:M→A and g:N→A there exists a homomorphism h:M→N such that f=gh. Here it is shown that the proposition above is false. Moreover, we give some relations among the class of projective modules the class of somisimple modules and the class of pseudo-projective modules. A charactrization of the semisimple rings. in terms of pseudo-projectivity,is also given.