文摘
Classical taut strings and their multidimensional generalizations appear in a broad range of applications. In this paper we suggest a general approach based on the K-functional of real interpolation that provides a unifying framework of existing theories and extend the range of applications of taut strings. More exactly, we introduce the notion of invariant K -minimal sets, explain their connection to taut strings and characterize all bounded, closed and convex sets in 46&_mathId=si1.gif&_user=111111111&_pii=S0022123615004346&_rdoc=1&_issn=00221236&md5=17de9aa908f57a16648f7f4bdf85981d" title="Click to view the MathML source">Rn that are invariant K -minimal with respect to the couple 46&_mathId=si155.gif&_user=111111111&_pii=S0022123615004346&_rdoc=1&_issn=00221236&md5=4c5a56bd440b3730fef71df6cc77f420" title="Click to view the MathML source">(ℓ1,ℓ∞).