Instructor: Max Schaefer
This lecture aims to provide students with the logical background knowledge needed to understand and appreciate the other lectures.
Hint: If you're having trouble with Exercise 3.2, try showing (φ → φ ∨ ψ) → (ψ → φ ∨ ψ) → φ ∨ ψ ⊢ φ ∨ ψ first. For this, it may in turn be helpful to consider ⊢ φ → φ ∨ ψ and ⊢ ψ → φ ∨ ψ.
You can use NJEdit to construct derivations in natural deduction. Currently, NJEdit is only tested with Firefox, Opera, and Safari; it does not work with Internet Explorer, as demonstrated during the tutorial.