Some Conditions for K_0(B(X))=0

摘要

Let A be an unital Banach algebra with the unital element I. We denote the set of (n×n)-matrices over A by Mn(A). The set of idempotent elements of A is denoted by P1(A):={P∈A: P2=P}, and accordingly the set of idempotent elements of Mn(A) is denoted by Pn(A):=P1(Mn(A)). We define P∞(A) :=∪n∈N Pn(A). In the set of P∞(A), for P,Q ∈ Pn(A), we say that P is (algebraic) equivalent to Q, if there exist A,B∈ Mn(A) such