## Prakash Panangaden

### From Logic to Stochastic Processes

I will give a survey of developments in the cc languages from plain cc
to - the as yet undiscovered - stochastic cc. The concurrent
constraint programming paradigm evolved out of concurrent logic
programming and had strong ties to logic. They abstracted from the
variety of control mechanisms that were current then in concurrent
logic programming languages and in functional languages with so called
"logic variables". The cc family was purely asynchronous.
In order to express reactive programs as in the family of synchronous
languages one had to introduce time. This led to the language tcc
which captures temporal notions. However, for synchronous programs one
needs an orthogonal idea as well, that of a default. The presence of
defaults introduces nonmonotonicity into the language. As we refine
the notion of time and introduce a mixture of continuous time as well
as discrete time we get a hybrid language called hcc.

Proabilistic cc was introduced at the end of the 1990s. It turned out
that one could use probabilities instead of defaults. In other words
the way probability works one can emulate the effect of defaults. I
will describe this evolution from logic programming languages to
languages for modelling stochastic processes through programming
examples and will conclude with possible extensions to a language
useful for state estimation. Much of the development is due to Vineet
Gupta, Radha Jagadeesan and Vijay Saraswat.

Host: Frank Pfenning

Appointments: Maury Burgwin

POP Seminar

April 6, 2001

3:30 p.m.

Wean Hall 8220