【摘要】 <正> 设 X 是一个 Banach 空间,假设（Ⅰ）—A 生成 X 上解析半群 e^-At,‖e^-At‖≤Me^μt,t≥0.令 λ₀>μ,则可定义（参看[1]）更多还原

【Abstract】 In this paper,we show the differentiability of the solution semigroup of adelay-differential equation in a Banach space X,（?）（t）+Au（t）=Bu（t—r）,where—A generates an analytic semigroup on X and B is a （λ₀+A）^α-bounded linear operatorin X （0≤α<1）.By the differentiability,the exponential stability of the systemwhen r=0 is proven to be stable under small r>0.Some examples concerningrobustness of stabilization under small feedback delays and determination of exactregions of stability for delay-parabolic equations are given.更多还原