A Concise Introduction to Logic, Patrick J. Hurley, Wadsworth, 2006, 9th ed,. 7.7, 9, p. 390

 Prove the logical truth.

1.     (P ⊃ Q) • (P ⊃ R) 2.     P 3.     P ⊃ Q 4.     Q 5.     P ⊃ R 6.     R 7.     Q • R 8.     P ⊃ (Q • R) 9.     [(P ⊃ Q) • (P ⊃ R)] ⊃ [P ⊃ (Q • R)]

/[(P ⊃ Q) • (P ⊃ R)] ⊃ [P ⊃ (Q • R)] ACP ACP 1 Simp 2,3 MP 1 Simp 2,5 MP 4,6 Conj 2-7 CP 1-8 CP