# Computing through a reusable surface Can a change of representation replace repeated computation with operations on a reusable surface? Explore encoding a spatial or temporal structure in an interference-like representation and computing changes or views from it; evaluate preparation cost, reconstruction cost, approximation, and representational limits. Status: open problem. Formulation and comparisons: reconstruction. Development: independent branch. ## Alternative representations ### An interference-based physical representation Affords: Connects spatial information with a physical surface. Limits or losses: Capacity and reconstruction depend on the actual physical setup. ### A computed surface for rendering or simulation Affords: Moves repeated work into a reusable representation. Limits or losses: Preparation and dynamic updates may cost more than direct computation. ## Tension A cheap view after expensive preparation is beneficial only for a suitable pattern of reuse. ## Challenge Which updates remain local after the transformation, and which require recomputing the surface? This challenge is an editorial prompt, not a claim that the evidence already resolved it. ## Proposed next move Compare total preparation, update, and query costs against direct computation for several reuse counts. Status: new model-proposed experiment or extension; not a reported result. ## Related problems - [How much of a whole can a part carry?](part-whole-traces.md) — shares a word with different meanings (retrospective_connection). Physical or computed surfaces and distributed social information can invite a holographic analogy, but they need separate encodings and validation. - [Finding a strategy by changing the representation](strategy-through-transformation.md) — asks whether transformation saves work (retrospective_connection). Both move effort into a representation. Preparation, planning, and execution costs must remain separately counted. ## Evidence anchors - basis-computation-through-a-surface: The material proposes translating physical interactions into changes in an interference pattern and asks about storage capacity. A later rendering proposal stores stable structures in a computational hologram and simulates moving parts through the surface, while asking whether the calculation becomes more complex or requires recomputing every section. [Editorial paraphrase; presence of a proposal does not verify its truth.] Root evidence and private recovery mappings are not part of this public release. [Open in the reader](../index.html#node=computation-through-a-surface) · [All problems](../CATALOG.md)