Definition

A correspondence structure on a family of locally described systems is the family of maps ρ_{i,e}: V_i → W_e that send each system’s local description into a space shared with a neighbour. Two local states agree on the edge e when ρ_{i,e}(x_i) = ρ_{j,e}(x_j). Collected over the network, the maps define a coboundary δ, and the jointly compatible assignments are its kernel, the global sections (Hansen and Ghrist, NOTE-1233). “Compatible”, “glued” and “frustrated” are all relative to a correspondence structure.

It is held in one of three ways (CLAIM-471):

how heldwhat it isexample the record has read
formedphysical interconnection fixes the maps: joining systems identifies some of their variables, so which local quantities must agree, and on what shared space, is set by how they are connected, while the law that holds at a junction is fixed beforehandBaez and Fong’s wiring, NOTE-1223: a map of terminals such as {1, 2} → {3} sets the joined potentials equal and adds the currents (Example 5.17), under the same Kirchhoff condition at every junction
discoveredmeasurement estimates a correspondence that already held; it is established only where the estimate is checked against evidence the measurement did not produce (CLAIM-143)Singer’s relative angles, NOTE-1224; Robinson’s geometric maps, NOTE-1221
adaptedan apparatus revises its own rules of comparisondiscourse sheaves, NOTE-1222

Forming sets which maps hold where. The joint behaviour they admit is their kernel, a constraint on states, and that is what CLAIM-471’s physical constraint formation names; the term keeps the two apart as map and kernel. Whether interaction among systems already connected ever changes the maps themselves, rather than which fixed kind of map holds on which edge, is QUESTION-282.

The distinctions it draws

  • From coupling. The coupling is what moves the states, for instance a dissipative Laplacian flow. The correspondence structure is what counts as agreement. A coupling attracts to the specified compatible space only if it enforces that structure (CASE-179). Setting the two apart is what makes the proposed study informative.
  • From a representation of it. An apparatus’s model of the correspondences is not the operative structure (CLAIM-471; A23 §IX: ĉ_t ≠ c_t in general). An adapted structure changes the apparatus. It changes the systems compared only if it is implemented.
  • Between the three ways of holding it. Only formation bears on the thesis that interaction generates constraints. Discovery is knowledge of a correspondence, and its adequacy needs evidence the correspondence does not itself produce (CLAIM-143). Adaptation can succeed at agreement by changing what is compared (THEORY-1088).

Why it was proposed

The word was doing three jobs in one claim before the owner’s review separated them, and four entries filed the same evening use it. QUESTION-282 asks when interaction changes the operative structure, and it needs the term to ask it. What would settle it: adoption if claims cite it to say which sense they mean; rejection if “gluing” and “compatibility” carry the distinction without it.