Who is Trieu from Catfish and Mandala: A Two-wheeled Voyage Through the Landscape and Memory of Vietnam and what is their importance?

Andrew's girlfriend, Trieu, was a Vietnamese-American he met when living in California. Her mother had died during the war, and as a result, her father put her up for adoption. She had only been reunited with her father for a bried time before Andrew met her. She is described as impassive.