LAZY CITY, RACHEL CONNOLLY’S EXACTING and wise debut novel, is a chronicle of echoes. Connolly tells the tale of two absences: Kate’s, a graduate student who dies before the book begins; and Erin’s, the novel’s protagonist. Erin had been Kate’s best friend, and Kate’s death so rattles her that it also makes her absent from herself. Lazy City takes place in the limbo that follows loss. It doesn’t treat the sharp pain of rupture—sharpness is among the reliefs Connolly withholds—but the lassitude that engulfs a mind after tragedy is over and before normal life resumes. Erin met Kate in graduate school in