What are the motifs in A Fire upon the Deep by Vernor Vinge?

Mythology and religion are recurring ideas. Readings in Computer Science and Applied Theology courses at Herte University prepare Ravna Bergsndot to interpret the formative myths of various cultures that she and Pham Nuwen encounter during the voyage of the Out of Bands II (OOB) from doomed Relay to the Tines' world. They fly with a mated pair of Skroderiders, a sentient plant species, Blueshell and Greenstalk. They come to Relay hoping to enlist Ravna's help in convincing the Vrinimi Organization to accept what they know about escapees from the disastrous Straumli Perversion. Shortly before leaving, Pham has had his mind filled with the knowledge of a Power, the Old One, as he becomes the first Power murdered in millennia. Part of the knowledge is the "Rider Myth."