arXiv AI By Nathalie Bertrand, Pranav Ghorpade, Senthil Rajasekaran, Sasha Rubin, Moshe Vardi

Categorizer Automata for Discounted-Sum Payoffs

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The paper introduces the categorizer automaton, a deterministic automaton that processes an infinite sequence of rewards and determines which of a finite set of bins contains the discounted sum. Unlike previous approaches that combine multiple comparator automata and yield exponential state spaces, the authors construct a categorizer automaton with a state space linear in the number of bins. They apply this construction to Markov decision processes, enabling synthesis of policies that maximize expected utility for discounted-sum payoffs, including cases with discontinuous or piecewise‑Lipschitz utility functions, achieving pseudo‑polynomial time algorithms and proving PSPACE‑hardness for the synthesis problem even with piecewise‑constant utilities.

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