1. G -> (H -> K) 2. (H v ~M) -> ~K 3. H ------------------------------------------------------- 4. H v ~M 3 Addition 5. ~K 2,4 Modus Ponens 6. (G * H) -> K 1 Exportation 7. ~(G * H) 6,5 Modus Tollens 8. ~G v ~H 7 De Morgan's Law 9. ~H v ~G 8 Commutation 10. ~~H 3 Double Negation 11. ~G 9,10 Disjunctive Syllogism