设0→BjEπA→0是有单位元C*-代数E的一个扩张,其中A是有单位元纯无限单的C*-代数,B是E的闭理想.当B是E的本性理想并且同时是单的、可分的而且具有实秩零及性质(PC)时,证明了K_0(E)={[p]| p是E/B中的投影};当B是稳定C*-代数时,证明了对任意紧的Hausdorff空间X,有 (C(X,E))/ _0(C(X,E))≌K_1(C(X,E)).
Let 0→B E A→0 be a short exact sequence of the unital C*-algebras, where A is a unital simple purely infinite C*-algebra,B is a closed ideal of the unital C*- algebra E.If B is an essential ideal of E and B is also simple,separable with RR(B) = 0 and(PC),then K_0(E) = {[p]| p is a projection in E / B};if B is a stable C~*-algebra,then (C(X,E))/_0(C(X,E))≌K_1(C(X,E)) for any compact Hausdorff space X.