New address: RFC Walters

New address: RFC Walters

[RFC Walters]

New email address
robert.walters@uninsubria.it

New mail address
Universita' dell'Insubria
Dipartimento di Scienze CC, FF e MM
Via Valleggio 11
22100 COMO, Italy

Web homepage
http://www.unico.it/~walters/


My recent papers are available there: the latest being
P. Katis, N. Sabadini, R.F.C. Walters
Feedback, trace and fixed point semantics
We introduce a notion of category with feedback-with-delay, closely 
related to the notion of traced monoidal category, and show that the
Circ construction of [JPAA 115: 141--178, 1997] is the free category 
with feedback on a symmetric monoidal category. Combining with the Int
construction of Joyal-Street-Verity [Math. Proc. Camb.Phil. Soc., 119,
447-468, 1996] we obtain a description of the free compact closed 
category on a symmetric monoidal category. We thus obtain a categorical 
analogue of the classical localization of a ring with respect to a 
multiplicative subset. In this context we define a notion of fixed-point 
semantics of a category with feedback which is seen to include a variety 
of classical semantics in computer science.
Others:
R. Rosebrugh, N. Sabadini, R. F. C. Walters, Minimization and Minimal 
Realization in Span(Graph), submitted
P. Katis, N. Sabadini, RFC Walters, Classes of finite state automata for 
which compositional minimization is linear time
Fabio Gadducci, Piergiulio Katis, Ugo Montanari, Nicoletta Sabadini, 
Robert F.C. Walters, Comparing cospan-spans and tiles via a Hoare-style 
process calculus