Homework for Philosophy 270, Fall 2012
Homework on §3.4—assigned Fri 9/21 and due Mon 9/24
(to PDF format)
Use a derivation to show the following fails to hold generally and confirm a counterexample lurking in a dead-end gap:
¬ (A ∧ B) ⊨ ¬ (A ∧ ¬ B)