Why was Adam described as having committed the sin and singled out for the command to repent, even though the sin was committed by both him and Eve?

The Quran confined itself to mentioning Adam's disobedience and repentance, without mentioning Eve's, even though they both shared in the sin. This is because the address from the beginning of the story was directed at Adam, and because Eve is subordinate to him and he is her role model. Thus, mentioning him sufficed for mentioning her. Similarly, attributing the sin to him, as in the Almighty's saying: "And Adam disobeyed his Lord and erred," sufficed for attributing it to her.