On the Algebra of Feedback and Systems with Boundary


Piergiulio Katis, N. Sabadini and R.F.C. Walters


Research Report 99-16
Date: 1 July 1999
To appear in Rendiconti del Seminario Matematico di Palermo


The notion of a category-with-feedback is introduced and two main classes of examples, constructed from input-feedback-output systems and spans of graphs, are described in detail. After surveying a range of applications to computer science, we concentrate on two new examples of the algebra: continuous linear systems, which includes a model of RLC circuits; and a formalization of double-entry accounting and other systems satisfying the continuity equation.

Key phrases

monoidal category. bicategory. feedback. concurrency. systems theory.

AMS Subject Classification (1991)

Primary: 18B20
Secondary: 68Q10, 18D05, 18D10, 93A05


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