Problema 2. Which of the following logical implications are valid? Justify your answer. Ejemplo: 1. {PQ,P}Q \begin{tabular}{|c|c|c|c|} \hline & & & Conclusin \\ \hline P & Q & PQ & Q \\ \hline T & T & T & T \\ \hline T & F & F & F \\ \hline F & T & T & T \\ \hline F & F & T & F \\ \hline & \multicolumn{2}{|c|}{ El argumento lgico es vlido } \\ \hline \end{tabular} 2. {PQ,PR}QR 3. {(PQ)R,R}P 4. {PQ,PQ}P