Terminal semantics for codata types in intensional Martin-L\"of type   theory
  In this work, we study the notions of relative comonad and comodule over a relative comonad, and use these notions to give a terminal coalgebra semantics for the coinductive type families of streams and of infinite triangular matrices, respectively, in intensional Martin-L\"of type theory. Our results are mechanized in the proof assistant Coq. 
Benedikt Ahrens and R\'egis Spadotti
cs.LO math.CT