Transformer Systems Lab
RoPE phase station
Carry the query-key route from the first gradient lab into positional geometry: predict what equal shifts preserve, then test a key-only transfer before moving to KV memory.
(R_p q)^T (R_q k) = q^T R(theta_q - theta_p) kone rotated Q/K pair
absolute position vs phase gap
commit equal-shift claim
move p, q, shift, frequency
phase table and dot score
relative phase controls score
key-only perturbation
KV memory handoff
Carry-in contract
The same attention route now asks what position changes.
RoPE is not a new destination or a long-context guarantee. It is the next operable object in the same Transformer Systems Lab case: the query-key score now contains rotation and relative phase.
Operable Station 03
RoPE: carry the query-key route into phase
Keep the same query/key attention object from the route. Now ask which part of the score survives when position changes.
Selected Object
One 2D query/key frequency pair
(R_p q)^T (R_q k) = q^T R(theta_q - theta_p) kUse one tiny coordinate pair so the cancellation is inspectable. The content vectors stay fixed; only the positions and frequency band move.
Prediction Checkpoint
Shift both positions by +3: q 2 -> 5, k 0 -> 3. What should happen to the query-key score?
Manipulation
Move positions, then re-predict.
Default witness band: enough movement to see the counterfactual.
Route spine
This station is finished only when it hands a usable invariant forward.
The route is deliberately narrow here: finish the phase invariant, preserve the first answer, save the evidence, then move one step into KV memory.