Release Message:  If it is provable in F that "if P is provable in F then P is true", then P is provable in F.

Description:  L ob did research on proof theory, modal logic and computability theory. He formulated L ob's theorem in 1955, as a formal version of L ob's paradox, that any statement that states that assert their own provability must be true (similar to G odel's incompleteness theorem).