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1999ICML

Policy Invariance under Reward Transformations Theory and Application to Reward Shaping

Andrew Y. Ng, Daishi Harada, Stuart Russell

What this work does

Characterizes potential-based shaping with the discount-consistent difference of successor and current potentials, preserving optimal policies under the stated MDP conditions.

Connection to discovery

A starting constraint when adding dense progress feedback to a sparse discovery objective.

Evidence

The proof separates sufficient invariance from worst-case necessity, while grid-world examples illustrate learning-speed effects and problematic nonpotential rewards.

Scope and limitations

Terminal-state and discount conditions matter. Adding an arbitrary novelty or learned progress bonus is not covered by the theorem. The original Stanford copy has broken text encoding; the Berkeley author copy was used for body review.

THE RESEARCH CONVERSATION

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