根据GIPS讲义第50页：Any change to a composite definition must not be applied retroactively
根据GIPS讲义第51页：Portfolios may not be moved into or out of composites except in the case of valid, documented,client-driven changes in investment objectives or guidelines or in the case of the redefinition of the composite.
请问当composite definition发生变化时，portfolios到底能否从composites中删除？
