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closed ideals, point derivations and weak amenability of extended little lipschitz algebras
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نویسنده
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mayghani maliheh ,alimohammadi davood
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منبع
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caspian journal of mathematical sciences - 2016 - دوره : 5 - شماره : 1 - صفحه:23 -35
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چکیده
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Let (x,d)be a compact metric space and let k be a nonempty compact subset of x. let alphain(0,1] and let lip(x,k,d^alpha) denote the banach algebra of all continuous complexvalued functions f on for which p_{(k,d^alpha)(f)=sup{frac{f(x)f(y)}{d^alpha(x,y)}: x,yin k, xneq y} when equipped with the algebra norm |f|_{lip(x,k,d^alpha}=|f|_x+p_{(k,d^alpha)(f), where |f|_x=sup{|f(x)| | xin x}. we denote by lip(x,k,d^alpha) the closed subalgebra of lip(x,k,d^alpha) consisting of all fin lip(x,k,d^alpha) for which frac{f(x)f(y)}{d^alpha(x,y)}longrightarrow 0 as d(x,y)longrightarrow x,yin k. in this paper we show that every proper closed ideal of (lip(x,k,d^alpha),|.|_{lip(x,k,d^alpha)})is the intersection of all maximal ideals containing it. we also prove that every continuous point derivation of lip(x,k,d^alpha) is zero. next we show that lip(x,k,d^alpha) is weakly amenable if $alphain(0,1/2). we also prove that lip(mathbb{t},k,d^{1/2}) is weakly amenable, where mathbb{t}={xinmathbb{c}| |z|=1}, d is the euclidean metric on t and k is a nonempty compact set in (mathbb{t},d).
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کلیدواژه
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banach function algebra ,extended lipschitz algebra ,point derivation ,weak amenability
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آدرس
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payame noor university, department of mathematics, ایران, arak university, faculty of science, department of mathematics, ایران
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پست الکترونیکی
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d-alimohammadi@araku.ac.ir
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Authors
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