The Space­time Pool by Cather­ine Asaro (2008) is a novella from Ana­log (sci-fi mag­a­zine). The story uses the Rie­mann sheet to explain the por­tal between alter­nate uni­verses. The story also con­tains hos­tile raiders, a fam­ily feud and a proph­esy.
The open­ing line starts with the fol­low­ing sen­tence, “[t]he hiker van­ished.” Janelle Aulair, a recent grad­u­ate from MIT, is hiking