“…(In our future work on discerning uniform decay properties of solutions to the multilayered FSI system (2)-( 5), the spectral information in Theorem 2 is also requisite; see e.g., the resolvent criteria in [27] and [12].) In showing the nonpresence of σ(A) on the imaginary axis -in particular, to handle the continuous spectrum of Awe will proceed in a manner somewhat analogous to what was undertaken in [7] (in which another coupled PDE system, with the coupling accomplished across a boundary interface, is analyzed with a view towards stability). However, the thin layer wave equation in (3) again gives rise to complications: In the course of eliminating the possibility of approximate spectrum of A on iR, we find it necessary to invoke the wave multipliers which are used in PDE control theory for uniform stabilization of boundary controlled waves: namely, inasmuch as each h j -wave equation in (3) carries the difference of the 3-D wave and heat fluxes as a forcing term, we cannot immediately control the thick wave trace ∂w ∂ν Γs in H − 1 2 (Γ s )norm, this control being needed for strong decay.…”