A certificate is a schedule of the underlying instance: one start time for every ordinary job, every long pending job and every short pending job, in the code of the instance. All times of the auxiliary problem are natural numbers, and a job starts before its deadline, so a solution takes at most quadratically more room than the instance. The verifier is a word RAM program: it takes the pair of instance and certificate apart, reads both with a one-pass tokenizer — once up to the end of the instance, to see that the instance is complete, and once to the end — checks the conditions on the deadlines of the pending jobs, checks every job against its availability interval, checks that in every connected pair one job meets its early deadline, and compares all pairs of jobs for overlap. Polynomial time on the word RAM transfers to a Turing machine.