This record presents a foundational manuscript proposing boundary-conditioned thermodynamics, a framework in which thermal equilibrium is treated not only as a static entropy maximum, but as a fixed point selected by physical exchange structures. In conventional thermodynamics, a thermal reservoir is often idealized as a featureless body characterized by a scalar temperature. The present work argues that this description can be incomplete when boundary processes themselves filter and reshape the accessible microscopic states. Gas--wall exchange, adsorption potentials, phonon-mediated re-emission, and boundary transition kernels can define a stationary state through a cycle condition, f^=Lf^. In this view, equilibrium is not only a state; it is also a fixed point of an exchange structure. The manuscript develops this idea through the Izumi-type mechanism, focusing on Bose--Einstein-type boundary kernels with unequal adsorption potentials. It introduces effective accessibility, effective entropy, kernel compatibility, structural non-isothermal fixed points, and the possibility of work extraction from kernel-conditioned structural bias. The work preserves microscopic energy conservation while examining whether the conventional scalar-temperature reservoir model is sufficient for all boundary-conditioned systems. The purpose of this record is to provide a theoretical foundation and reference document for future discussion, simulation, and experimental testing. The immediate experimental priority is not engine construction, but verification or falsification of the predicted structural non-isothermal fixed point and its dependence on adsorption asymmetry. This work is intended as a starting point for a broader research direction in which thermodynamics is extended from the study of material states to the study of exchange structures, boundary kernels, and the fixed points they select.
Makoto Izumi (Fri,) studied this question.