Constitutive selection of thermal evolution operators by active microstructures

We investigate how active microstructures select the operatorial structure of thermal evolution. Rather than postulating alternative heat-transport laws, we derive families of thermal evolution equations from the balance structure associated with active microstructural interactions under different classes of constraints. The constitutive architecture of the material determines not only transport coefficients but also the very class of the thermal evolution operator. The analysis reveals a hierarchy of constitutively selected thermal regimes, each characterized by specific coercive quantities and associated natural functional topologies. In this perspective, admissible evolution spaces are not imposed as external analytical choices but emerge as constitutive consequences of the underlying microstructural interactions. The proposed viewpoint provides a unified framework in which classical Fourier conduction, generalized non-Fourier evolution, and microstructure-induced pseudoparabolic effects appear as different manifestations of a common constitutive mechanism. To preserve the physical character of the theory, no artificial regularization devices are introduced, and the analytical conclusions are restricted to the coercive structures generated by the physical balances themselves.