Delegation for Search Problems

Authors Justin Holmgren, Andrea Lincoln, Ron D. Rothblum

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Author Details

Justin Holmgren
  • NTT Research, Sunnyvale, CA, USA
Andrea Lincoln
  • University of California Berkeley, CA, USA
Ron D. Rothblum
  • Technion, Haifa, Israel


We thank Benny Applebaum for helpful discussions.

Cite AsGet BibTex

Justin Holmgren, Andrea Lincoln, and Ron D. Rothblum. Delegation for Search Problems. In 49th International Colloquium on Automata, Languages, and Programming (ICALP 2022). Leibniz International Proceedings in Informatics (LIPIcs), Volume 229, pp. 73:1-73:18, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2022)


The theory of proof systems in general, and interactive proofs in particular, has been immensely influential. Such proof systems allow a prover to convince a verifier whether a given statement is true or not - namely to solve a decision problem. In this work we initiate a study of interactive proofs for search problems. More precisely, we consider a setting in which a client C, given an input x, would like to find a solution y satisfying (x,y) ∈ R, for a given relation R. The client wishes to delegate this work to an (untrusted) advisor A, who has more resources than C. We seek solutions in which the communication from A is short, and, in particular, shorter than the length of the output y. (In particular, this precludes the trivial solution of the advisor sending y and then proving that (x,y) ∈ R using a standard interactive proof.) We show that such search delegation schemes exist for several problems of interest including (1) longest common subsequence (LCS) and edit distance, (2) parsing context-free grammars and (3) k-SAT.

Subject Classification

ACM Subject Classification
  • Theory of computation → Interactive proof systems
  • Interactive Proofs
  • Fine-Grained Complexity
  • Delegation


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