If the statement 'No professors are materialists' is given as true, then which of the following statements could be inferred to be true?

From 'No professors are materialists' being true, 'Some professors are not materialists' is true.

This move is subalternation, from the universal down to the particular.

The E proposition entails its subaltern, the O proposition.

If none of the professors are materialists, then some certainly are not.

The truth of the universal negative carries down to the particular negative.