Complex sentence: Löb did research on proof theory, modal logic and computability theory, and formulated Löb's theorem in 1955, as a formal version of Löb's paradox, that statements that assert their own provability must be true (similar to Gödel's incompleteness theorem).
Split into simpler sentences: Löb did research on proof theory, modal logic and computability theory. He formulated Löb's theorem in 1955, as a formal version of Löb's paradox, that statements that assert their own provability must be true (similar to Gödel's incompleteness theorem).