At the end, when they are watching the video at the erudite head quaters. It features Amanda Ritter. At the end of the video, she says : "My name will be Edith Prior," .This confused me alot. Prior is also Tris's last name. But..... Her mums name is NOT Edith. It was proven when Tris was under the truth serum. She got asked the question, who are you parents? She then answered: Andrew and Natalie Prior. Who is Edith??
This answer contains spoilers… (view spoiler)[Since her last name is Prior, she is a relative of Tris' on her father's side. As she said in the video, she is one of the first people to be a part of the new faction society. We don't know how many generations of Priors have lived in the city, since we don't know when the people were placed there, so Edith Prior could be her grandmother or great grandmother or great great grandmother. We don't know for sure. (hide spoiler)]