Proof of `Computing the scatter type`
groundedproofs/Lax185574Proofs/ComputeScatterType.lean · lax-185574
What this proof establishes
Assuming the claims on the left, the claim on the right holds — checked by the archive's pipeline. Proof code is not displayed here.
In the paper
- page 46 of this submission's paper
Description
The program runs the glue program and the program of the rank shift lemma in the loop driver , as in the proof of the lemma on computing scatter types. The first round reads the graph, and , skips the distance matrix and reads the family of type trees. For it outputs the empty scatter type. Otherwise the rounds ask for the shifts of the entries of the list of the family trees followed by the answers, one by one, so that the answers are the trees for and all vertices , in this order. After a dummy call the final round reads the graph, and the answers and computes the scatter type (). Its greedy scans test whether a vertex is within distance of a chosen vertex by one entry of the row of of the chosen vertex, in place of a breadth-first search. The script has calls. Every run inside the driver is right at an admissible word length: the runs of the glue program because their values are below a constant in times the cube of , the runs of the rank shift because their queries are admissible at the word lengths of their regions. The time is that of the first round, , and of the final round, , plus middle rounds of time and calls of time .
The proof is carried out for the notion , and transferred to through .