1a entails 1b

1a. The president was assassinated

1b. The president is dead 

 

2a presupposes 2b

2a. Sam regretted eating the banana

2b. Sam ate the banana

Sentence 2a presupposes sentence 2b in which the presupposition is that she ate the banana.

The presupposition trigger is regretted.

 

3a presupposes 3b 

3a. Tyler stopped turning into a werewolf every full moon

3b. Tyler used to turn into a werewolf every full moon

Sentence 3a presupposes sentence 3b in which the presupposition is that Tyler was a werewolf.

The presupposition trigger is stopped.