I don't know the grammar terminology (ESL, and all), but AIUI, in your examples, the one-word antecedent would be, in order, "president" and "singer".
What I do understand though is the wider point: ambiguous sentences are a pain for AI and humans alike; if you use a pronoun, make sure there is exactly one candidate it could refer to.
What I do understand though is the wider point: ambiguous sentences are a pain for AI and humans alike; if you use a pronoun, make sure there is exactly one candidate it could refer to.