Homework on §4.2—assigned Fri 10/1 and due Mon 10/4

Construct a derivation to show the following and note all of the possible ways of developing the derivation at the first stage (do not use any rules for disjunction other than PC and PE—i.e., do not use the rules MTP and Wk that are introduced in §4.3):

A ∨ B, ¬ (B ∧ ¬ C) ⊨ A ∨ C