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تسجيل مستخدم جديدCharacterizing semigroups $X$ with commutative extensions $varphi(X)$, $lambda(X)$, $N_2(X)$, $upsilon(X)$
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We characterize semigroups $X$ whose semigroups of filters $varphi(X)$, maximal linked systems $lambda(X)$, linked upfamilies $N_2(X)$, and upfamilies $upsilon(X)$ are commutative.
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