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ICFP 2018
Sun 23 - Sat 29 September 2018 St. Louis, Missouri, United States
Mon 24 Sep 2018 17:25 - 17:47 at Stifel Theatre - Probabilistic Programming and Learning Chair(s): Michael Sperber

We present a complete reasoning principle for contextual equivalence in an untyped probabilistic language. The language includes continuous (real-valued) random variables, conditionals, and scoring. It also includes recursion, since the standard call-by-value fixpoint combinator is expressible.

We demonstrate the usability of our characterization by proving several equivalence schemas, including familiar facts from lambda calculus as well as results specific to probabilistic programming. In particular, we use it to prove that reordering the random draws in a probabilistic program preserves contextual equivalence. This allows us to show, for example, that

(let x = e1 in let y = e2 in e3) = (let y = e2 in let x = e1 in e3)

(provided $x$ does not occur free in $e_2$ and $y$ does not occur free in $e_1$) despite the fact that $e_1$ and $e_2$ may have sampling and scoring effects.

Mon 24 Sep
Times are displayed in time zone: (GMT-05:00) Guadalajara, Mexico City, Monterrey change

16:40 - 18:10: Research Papers - Probabilistic Programming and Learning at Stifel Theatre
Chair(s): Michael SperberActive Group GmbH
icfp-2018-papers16:40 - 17:02
Conal ElliottTarget, USA
icfp-2018-papers17:02 - 17:25
Adam ŚcibiorUniversity of Cambridge and MPI Tuebingen, Ohad KammarUniversity of Oxford, Zoubin GhahramaniUniversity of Cambridge
icfp-2018-papers17:25 - 17:47
Mitchell WandNortheastern University, USA, Ryan CulpepperCzech Technical University, Theophilos GiannakopoulosBAE Systems, Inc., Andrew CobbNortheastern University
icfp-2018-papers17:47 - 18:10
José Bacelar AlmeiraUniversity of Minho & INESC TEC, Alcino CunhaUniversity of Minho and INESC TEC, Portugal, Nuno MacedoUniversity of Minho & INESC TEC, Hugo PachecoUniversity of Minho, Portugal, José ProençaHASLab/INESC TEC & University of Minho