Match the following:
i. A proof that the implication $p \rightarrow q$ is true based
on the fact that $p$ is false
ii. A proof that the implication $p \rightarrow q$ is true based
on the fact that $q$ is true
iii. A proof that the implication $p \rightarrow q$ is true that
proceeds by showing that $q$ must be true when $p$ is true
iv. A proof that the implication $p \rightarrow q$ is true that
proceeds by showing that $p$ must be false when $q$ is false
Gatecse