Science Talk

Eukie_M_SHIRAISHI · Guest

Select the truths from the following 1) – 5)

1) If [ if P, then Q ], then there can be the case in which [ if not-P,
then not-Q ].

2) If [ if P, then Q or R ], then either [ if P, then Q ] or [ if P,
then R ].

3) If and only if [P and not-Q] is a contradiction, [ if P, then Q ]
holds true.

4) If and only if there is a case in which Q does not hold true despite
that P holds true, [ if P, then Q ] does not hold true.

5) If there is a case in which P does not hold true, then P is a
contradiction.