ALOGTIME and a conjecture of S.A. Cook

Using sequential, machine-independent characterizations of the parallel complexity classes AC/sup k/ and NC/sup k/, the author establishes a conjecture of S.A. Cook (1975) regarding polynomial size Frege proofs for a certain infinite family. A related result is established with constant formula-depth polynomial size Frege proofs for a system AV related to uniform AC/sup 0/ functions.<<ETX>>