The Universal Coherence Theorem: Substrate Invariance of Evaluation Dynamics

This paper states the Universal Coherence Theorem (UCT): the fixed-point structure of evaluation dynamics is substrate-invariant. If a coherence-preserving map exists between two substrates such that Φ_B(τ(x)) = τ(Φ_A(x)), fixed points are preserved. Biological cognition, digital computation, and institutional systems are all implementations of the same coherence architecture — they differ in the translation between substrates, but not in the fixed point. Truth is the same attractor in every substrate that can sustain contractive evaluation dynamics. The UCT completes the three-theorem core of the Spektre corpus alongside the ECT and CIT.