Authors: Tarmo Uustalu, Varmo Vene
Title: Signals and comonads
Abstract: 
We give a practical demonstration of the claim that, just as
monads can be used as an abstraction of notions of computation,
comonads abstract notions of values-in-context. We discuss two
comonads whose coKleisli arrows are general resp. causal stream
functions, i.e., transformers of signals in discrete time.  In
particular, we discuss the application of such comonads as modularity
tools in programming and in semantic descriptions of intensional and
dataflow languages a la Lucid and Lustre. We also compare our approach
to that of "arrows" by J. Hughes.
(This abstract and title are tentative, I might wish to detail them.)