Zero-one permanent is ≠P-complete, a simpler proof

Valiant (1979) proved that computing the permanent of a 01-matrix is ≠P-complete. The authors present another proof for the same result. The proof uses `black box´ methodology, which facilitates its presentation. They also prove that deciding whether the permanent is divisible by a small prime is ≠P-hard. They conclude by proving that a polynomially bounded function can not be ≠P-complete under `reasonable´ complexity assumptions