Lattices in Computer Science Lecture 7 Limits on inapproximability Lecturer : Oded Regev Scribe : Michael Khanevsky Let us recall the promise problem

@inproceedings{EFINITION2005LatticesIC,
  title={Lattices in Computer Science Lecture 7 Limits on inapproximability Lecturer : Oded Regev Scribe : Michael Khanevsky Let us recall the promise problem},
  author={. D EFINITION},
  year={2005}
}
  • . D EFINITION
  • Published 2005
It is easy to see that GapCVPγ ∈ NP for anyγ ≥ 1. Indeed, a witness is a vector u ∈ L(B) such that ‖v − u‖ ≤ d. This witness is of polynomial size (since the length of the vector is at most ‖v‖ + d) and it can be verified efficiently (simply check that ‖v − u‖ ≤ d). What about the complement of GapCVPγ? In other words, for what values of γ is GapCVPγ ∈ coNP… CONTINUE READING