A new converse in rate-distortion theory

@article{Kostina2012ANC,
  title={A new converse in rate-distortion theory},
  author={Victoria Kostina and Sergio Verd{\'u}},
  journal={2012 46th Annual Conference on Information Sciences and Systems (CISS)},
  year={2012},
  pages={1-6}
}
This paper shows new finite-blocklength converse bounds applicable to lossy source coding as well as joint source-channel coding, which are tight enough not only to prove the strong converse, but to find the rate-dispersion functions in both setups. In order to state the converses, we introduce the d-tilted information, a random variable whose expectation and variance (with respect to the source) are equal to the rate-distortion and rate-dispersion functions, respectively.