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derivated map; biordered set; admissible order
Several authors have defined operational quantities derived from the norm of an operator between Banach spaces. This situation is generalized in this paper and we present a general framework in which we derivate several maps $X\rightarrow \Bbb R$ from an initial one $X\rightarrow \Bbb R$, where $X$ is a set endowed with two orders, $\leq $ and $\leq ^{\ast }$, related by certain conditions. We obtain only three different derivated maps, if the initial map is bounded and monotone.
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