Using universal property , we can define general ( pre ) cover and ( pre ) envelope , such as gorenstein injective ( projective or flat ) ( pre ) cover and ( pre ) envelope , 5 - torsion free ( pre ) cover etc . in a word , problems on ( pre ) over and ( pre ) envelope have aroused considerable debate in the academic circle , which embodies flexible use of tools of homological algebra in studying categories of rings and modules 而且利用泛性我们又可定义更广泛意义上的包、盖问题，例如： gorenstin内射(平坦、投射)包(盖) ， s -无挠预盖，等等。用这类比内射(平坦、投射)更广泛意义上的特殊模又能刻画一些环。总之，包、盖问题是当今非常活跃的研究课题，体现了同调代数在环模范畴研究中灵活运用。
In this paper , we define the concepts of the star semirings of no star factor , the star semimodules of no star factor , the dual star semimodules and the reflexive star semimodules in the basis of the star system which is introduced by professor chne pei - ci , and obtain some properties 摘要在引入星系统的基础上，进一步引入了无星因子*幺半环、无星因子*幺半模、对偶星幺半模与自反星幺半模等概念，并把半模范畴中对偶性与自反性的一些结果推广到星幺半模范畴中。
In the last section , we discuss the covers and envelopes both of which are of great importance in the field of ring theories . by the morita context functors we can transform from rx - cover ( envelope ) into sx - f - cover ( envelope ) . finally they are further characterized by the particular properties of the direct limit 在第四部分中，我们对环论中十分重要的内容? ?包与盖进行探讨，通过一类特殊的模范畴_ rx ( _ sx ) ，使_ rx -包(盖)在moritacontext函子作用下转化为_ sx -包(盖) ，最后利用正向极限的特性，进一步刻画这类特殊的包与盖。
Firstly , well - log data is main data in reservoir geological modeling integrated seismic and well - log data , seismic data only makes restriction function , and seismic data is main in seismic inversion , well - log data only makes restriction function . secondly , reservoir geological modeling integrated seismic and well - log data not only includes deterministic modeling methods , but also includes stochastic modeling methods , and seismic inversion belongs to deterministic modeling domain . they also have some difference ir , modeling arithmetic and precision 但两者之间存在很大的不同，地震与地质资料综合储层地质建模以井资料为主，地震资料起约束作用，而地震反演以地震资料为主，井资料起约束作用；前者即包括确定性建模方法，也包括随机建模方法，而后者从广义上讲属确定性建模范畴；两者在建模算法和精度等方面还有所不同。
