Rational proofs

We study a new type of proof system, where an unbounded prover and a polynomial time verifier interact, on inputs a string x and a function f , so that the Verifier may learn f (x). The novelty of our setting is that there no longer are “good” or “malicious” provers, but only rational ones. In essen...

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Main Authors: Azar, Pablo Daniel, Micali, Silvio
Format: Article
Language:en_US
Published: © Association for Computing Machinery, New York, NY, USA 2022
Online Access:https://doi.org/10.1145/2213977.2214069
https://hdl.handle.net/1721.1/141708
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author Azar, Pablo Daniel
Micali, Silvio
author_facet Azar, Pablo Daniel
Micali, Silvio
author_sort Azar, Pablo Daniel
collection MIT
description We study a new type of proof system, where an unbounded prover and a polynomial time verifier interact, on inputs a string x and a function f , so that the Verifier may learn f (x). The novelty of our setting is that there no longer are “good” or “malicious” provers, but only rational ones. In essence, the Verifier has a budget c and gives the Prover a reward r ∈ [0, c] determined by the transcript of their interaction; the prover wishes to maximize his expected reward; and his reward is maximized only if he the verifier correctly learns f (x). Rational proof systems are as powerful as their classical counterparts for polynomially many rounds of interaction, but are much more powerful when we only allow a constant number of rounds. Indeed, we prove that if f ∈ #P, then f is computable by a one-round rational Merlin-Arthur game, where, on input x, Merlin’s single message actually consists of sending just the value f(x). Further, we prove that CH, the counting hierarchy, coincides with the class of languages computable by a constant-round rational Merlin- Arthur game. Our results rely on a basic and crucial connection between rational proof systems and proper scoring rules, a tool developed to elicit truthful information from experts.
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spelling mit-1721.1/1417082022-04-07T03:37:31Z Rational proofs Azar, Pablo Daniel Micali, Silvio We study a new type of proof system, where an unbounded prover and a polynomial time verifier interact, on inputs a string x and a function f , so that the Verifier may learn f (x). The novelty of our setting is that there no longer are “good” or “malicious” provers, but only rational ones. In essence, the Verifier has a budget c and gives the Prover a reward r ∈ [0, c] determined by the transcript of their interaction; the prover wishes to maximize his expected reward; and his reward is maximized only if he the verifier correctly learns f (x). Rational proof systems are as powerful as their classical counterparts for polynomially many rounds of interaction, but are much more powerful when we only allow a constant number of rounds. Indeed, we prove that if f ∈ #P, then f is computable by a one-round rational Merlin-Arthur game, where, on input x, Merlin’s single message actually consists of sending just the value f(x). Further, we prove that CH, the counting hierarchy, coincides with the class of languages computable by a constant-round rational Merlin- Arthur game. Our results rely on a basic and crucial connection between rational proof systems and proper scoring rules, a tool developed to elicit truthful information from experts. This material is based on work supported by the U.S. Office of Naval Research, Grant No. N00014-09-1-0597. Any opinions, findings, conclusions or recommendations therein are those of the author(s) and do not necessarily reflect the views of the Office of Naval Research. 2022-04-06T15:42:29Z 2022-04-06T15:42:29Z 2012-05-19 Article https://doi.org/10.1145/2213977.2214069 https://hdl.handle.net/1721.1/141708 Azar, P. D., & Micali, S. (2012). Rational proofs. Proceedings of the Forty-Fourth Annual ACM Symposium on Theory of Computing (STOC '12), 1017–1028. en_US Attribution-NonCommercial-NoDerivs 3.0 United States http://creativecommons.org/licenses/by-nc-nd/3.0/us/ application/pdf © Association for Computing Machinery, New York, NY, USA
spellingShingle Azar, Pablo Daniel
Micali, Silvio
Rational proofs
title Rational proofs
title_full Rational proofs
title_fullStr Rational proofs
title_full_unstemmed Rational proofs
title_short Rational proofs
title_sort rational proofs
url https://doi.org/10.1145/2213977.2214069
https://hdl.handle.net/1721.1/141708
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