The Universe as a Gravitationally Coupled Computer: Architecture, Algorithms, and the Program-as-Signature Principle — A Companion Note to P38

This note is a direct companion to P38 (The Preonic Universe as a Gravitationally Coupled Computational System). It takes P38's Gravitational Feedback Amplification Theorem (GFAT) as given and develops three things P38 leaves compressed, without introducing any new physical mechanism. - Architecture: an explicit account of memory (the complete preonic configuration), processor (the resultant p-gravitational and n-gravitational interactions), and why the preonic substrate has no Von Neumann bottleneck — state and update rule are the same physical fact. - Compatible algorithm classes: a working reference organizing what P38 §7–8 already establishes the gravitational channel can and cannot run — global optimisation, pattern detection in global state, distributed consensus, forward-causal search, and gravitational tomography extraction — tied to the two things the channel withholds (addressability, reversibility). - The Program-as-Signature Principle: a clarification, proposed here for the first time, that P38's Definition 2 already implies there is no separate "signature layer" to design. Under QGD's discrete momentum-exchange constraints, a program's causal pattern and its identifying signature are the same physical object, not two design layers. On quantum computing, this note follows P3 and P7 directly rather than the portfolio's Bell-correlation work, which addresses a different question. P3 and P7 jointly preclude the ontological resource (superposition, reversible gates) the standard exponential-speedup argument requires — but P3 §5 itself leaves open, explicitly and by name, whether the deterministic preonic dynamics underlying a real device reproduce the same complexity reduction. That open question, not any Bell-correlation result, is stated here as the honest boundary of the comparison.