Strict contractions and exotic SO_0(d,1) quotients
  For d < 5, we describe an elementary construction of nonzero degree, strict contractions between closed, oriented hyperbolic d-oribifolds. Appealing to work of Gueritaud-Kassel and Tholozan, these examples determine exotic quotients of SO_0(d,1). 
Grant S. Lakeland and Christopher J Leininger
math.GT