The \(\mathcal{JK}\)-Method of Interpolation for Finite Families of Banach Spaces

Let \(\mathcal{I}\) be an operator ideal of those considered here. We present a method of interpolation for finite families such that if \(\bar{A}\) and \(\bar{B}\) are (n+1)-tuples, \(T\) is an interpolation operator and <A>, <B> are the interpolation spaces obtained by this method then, \(T\) : <A> \(\rightarrow\) <B> is in \(\mathcal{I}\) if and only if the operator from the intersection \(\mathcal{J}\) (\(\bar{A}\)) into the sum \(\mathcal{S}\)(\(\bar{B}\)) is in \(\mathcal{I}\).