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تسجيل مستخدم جديدFinite Quasihypermetric Spaces
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Let $(X, d)$ be a compact metric space and let $mathcal{M}(X)$ denote the space of all finite signed Borel measures on $X$. Define $I colon mathcal{M}(X) to R$ by $I(mu) = int_X int_X d(x,y) dmu(x) dmu(y)$, and set $M(X) = sup I(mu)$, where $mu$ ranges over the collection of measures in $mathcal{M}(X)$ of total mass 1. The space $(X, d)$ is emph{quasihypermetric} if $I(mu) leq 0$ for all measures $mu$ in $mathcal{M}(X)$ of total mass 0 and is emph{strictly quasihypermetric} if in addition the equality $I(mu) = 0$ holds amongst measures $mu$ of mass 0 only for the zero measure. This paper explores the constant $M(X)$ and other geometric aspects of $X$ in the case when the space $X$ is finite, focusing first on the significance of the maximal strictly quasihypermetric subspaces of a given finite quasihypermetric space and second on the class of finite metric spaces which are $L^1$-embeddable. While most of the results are for finite spaces, several apply also in the general compact case. The analysis builds upon earlier more general work of the authors [Peter Nickolas and Reinhard Wolf, emph{Distance geometry in quasihypermetric spaces. I}, emph{II} and emph{III}].
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Let $(X, d)$ be a compact metric space and let $mathcal{M}(X)$ denote the space of all finite signed Borel measures on $X$. Define $I colon mathcal{M}(X) to R$ by [I(mu) = int_X int_X d(x,y) dmu(x) dmu(y),] and set $M(X) = sup I(mu)$, where $mu$ rang
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