给出C*-代数α-比较性的等价刻画:对于单的含单位元的稳定有限的C*-代数A而言,A具有α-比较性,当且仅当对于任意的(a),(b)∈W(A),若α-·dr(α-)〈d(b)(Vr∈QT(A)),则(a)≤(b)在Cuntz半群w(A)中成立.利用此刻画,证明了具有α-比较性的C*-代数一定具有弱比较性;若A具有α-比较性,其中α=m+1,则A具有正元的强迹m-比较性;对于满足Kirchberg-Rordam条件的C*-代数,缪一稳定、严格比较、α-比较性(α=m+1)、强迹m-比较性、弱比较性以及局部弱比较性彼此等价;若α:=inf{α’∈(1,00)I∥具有α’-比较}〈00,则A具有α-比较性.
We give an equivalent characterization for the α-comparison property of C*-algebras: any simple unital stably finite C*-algebra ~ has the a-comparison prop- erty, if and only if, for any (a), (b) e W(~a'), a. d~-(a) 〈 d~(b)(VT ~ QT(~)) implies that (a) 〈 (b) holds in W(A). Using this characterization, we prove the following results: C*-algebras with a-comparison property have weak comparison; C*-algebras with α-comparison property for α = m + 1 have strong tracial m-comparison of posi- tive elements; α-stability. strict comparison, α-comparison property for α= m+l, strong tracial m-comparison, weak comparison and local weak comparison all agree for the C*-algebras satisfying the conditions given by Kirchberg-RCrdam; if α-:= inf{c∈ (1, ∞)A has the α'-comparison property} 〈 ∞, then α' has the a-comparison prop- erty.