We present a generalization of H\"older duality to algebra-valued pairings via Lᵖ-modules. H\"older duality states that if p (1, ) and p^ are conjugate exponents, then the dual space of Lᵖ () is isometrically isomorphic to L^p^{} (). In this work we study certain pairs (Y, X), as generalizations of the pair (L^p^{} (), Lᵖ () ), that have an Lᵖ-operator algebra valued pairing Y X A. When the A-valued version of H\"older duality still holds, we say that (Y, X) is C*-like. We show that finite and countable direct sums of the C*-like module (A, A) are still C*-like when A is any block diagonal subalgebra of d d matrices. We provide counterexamples when A Mdᵖ (C) is not block diagonal.
Calin et al. (Sun,) studied this question.