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We present a formalization of parts of Melvin Fitting's book "First-Order Logic and Automated Theorem Proving". The formalization covers the syntax of first-order logic, its semantics, the model existence theorem, a natural deduction proof calculus together with a proof of correctness and completeness, as well as the Löwenheim-Skolem theorem.
July 21, 2018
Proved completeness theorem for open formulas. Proofs are now written in the declarative style. Enumeration of pairs and datatypes is automated using the Countable theory.