Proof of `Interval scheduling is fixed-parameter tractable for the machines and the largest processing time` (1st statement)
groundedproofs/Lax470956Proofs/Theorem3Fpt.lean · lax-470956
What this proof establishes
no assumptions
Assuming the claims on the left, the claim on the right holds — checked by the archive's pipeline. Proof code is not displayed here.
Description
The explicit bound of the first form is stated for the words that leave room for the table. Fixed-parameter tractability is stated for every word whose entries fit, and there the table may not be addressable: a machine with cells cannot hold entries when that exceeds , although every entry of the word is a word.
The program first computes by repeated multiplication, testing each step by a division so that no intermediate value exceeds , and compares it with .
If the table has at most entries, the sweep of the first form runs unchanged, within instructions.
Otherwise , where is the parameter, so the word, and with it the number of jobs , is bounded by a function of the parameter alone. The program then tries every schedule. An odometer of digits in base runs through them, each digit naming a machine or rejecting the job. Each string is checked against the word: every job on an eligible machine, no two overlapping jobs on one machine, and the weight added up with a cap at the threshold. There are strings, each tested in time polynomial in the length, and .
The function of the parameter is , much larger than the of the first form, which is the cost where the table fits.