设R是环.引入了n-P-投射模和强-p-投射模的概念,并证明了M是n-P-投射模当且仅当M是Pn-预包络f:A→B的余核,其中B是投射模；如果R是左凝聚右完全环,那么(PP,PP⊥)是完备的余挠理论,(SPP,SPP-)是完备遗传的余挠理论,其中PP表示P-投射模类,SPP表示强-p-投射模类.%Let R be any ring. The concepts of n-P-protective modules and strongly-P-projective modules are introduced. It is shown that M is n-P-projective module if and only if M is a cokernel of a Pn-preenvelope f:A→B with B protective; if R is a left coherent and right perfect ring, then (PP,PP⊥ ) is a perfect cotorsion theory, and (SPP,SPP⊥) is a perfect hereditary cotorsion theory, where PP denotes the class of all P-projective modules, and SPP denotes the class of all strongly-P-projective modules.
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